Further, some sins are mortal in virtue of their species [‘Ex genere,’ genus in this case denoting the species], as murder and adultery. (Saint Thomas Aquinas. Summa Theologica, I-II, q. 72, a. 5)

Everyone who divorces his wife and marries another commits adultery, and the one who marries a woman divorced from her husband commits adultery. (Lk 16:18)

To the married, however, I give this instruction (not I, but the Lord): a wife should not separate   from her husband – and if she does separate she must either remain single or become reconciled to her husband – and a husband should not divorce his wife. (1 Cor7:10-11)

Contracting a new union, [after a divorce] even if it is recognized by civil law, adds to the gravity of the rupture: the remarried spouse is then in a situation of public and permanent adultery. (Catechism of the Catholic Church, no. 2384)

Is it sufficient for a Christian to get only the civil marriage or contract?
For a Christian, it is not sufficient to get only the civil contract, because it is not a sacrament, and therefore not a true marriage.
In what condition would the spouses be who would live together united only by a civil marriage?
Spouses who would live together united by only a civil marriage would be in an habitual state of mortal sin, and their union would always be illegitimate in the sight of God and of the Church. (Catechism of Saint Pius X, The Sacrament of Marriage, no. 24-25)

Because no Catholic is ignorant or cannot know that matrimony is truly and properly one of the seven sacraments of the evangelical law, instituted by Christ the Lord, and that for this reason, there can be no marriage between the faithful without there being at one and the same time a sacrament, and that, therefore, any other union of man and woman among Christians, except the sacramental union, even if contracted under the power of any civil law, is nothing else than a disgraceful and death-bringing concubinage very frequently condemned by the Church, and, hence, that the sacrament can never be separated from the conjugal agreement. (Denzinger -Hünermann 2998. Pius IX. Allocution Acerbissimum vobiscum, September 27, 1857)

The remarriage of persons divorced from a living, lawful spouse contravenes the plan and law of God as taught by Christ. They are not separated from the Church, but they cannot receive Eucharistic communion. They will lead Christian lives especially by educating their children in the faith. (Catechism of the Catholic Church, no. 1665)

The sacrament demands that the indissolubility of matrimony, and that the repudiated may not unite with another person not even for children. (Saint Augustine of Hippo. De Genesi ad litteram, Book 9, Ch.7, no. 12)

Because they who refuse to be subject to the law of God are surely reputed the enemies of God. (Pius X. Encyclical Communionum rerum, no. 21, April 21, 1909)

If anyone says that the Church errs, inasmuch as she has taught and still teaches that in accordance with evangelical and apostolic doctrine the bond of matrimony cannot be dissolved because of adultery of one of the married persons, and that both, or even the innocent one, who has given no occasion for adultery, cannot during the lifetime of the other contract another marriage, and that he, who after the dismissal of the adulteress shall marry another, is guilty of adultery, and that she also, who after the dismissal of the adulterer shall marry another: let him be anathema. (Denzinger-Hünermann 1807. Council of Trent, Session XXIV, Doctrine Concerning the Sacrament of Matrimony, November 11, 1563)

But if you do not heed me and do not keep all these commandments, if you reject my precepts and spurn my decrees, refusing to obey all my commandments and breaking my covenant, then I, in turn, will give you your deserts. (Lev 26:14-16)

But those habitually guilty of sin are their own worst enemies. (Tob 12:10)

But since all mortal sins, even those of thought, make men children of wrath (Ep 2,3) and enemies of God, it is necessary to ask pardon for all of them from God by an open and humble confession. (Denzinger-Hünermann 1680. Council of Trent, Session XIII, October 11, 1551)

Who are the living members of the Church?
The living members of the Church are the just, and the just alone, that is, those who are actually in the grace of God.
And who are the dead members?
The dead members of the Church are the faithful in mortal sin. (Catechism of Saint Pius X, Ninth Article, no. 25-26)

God Himself dwells in righteous bodies. But the bodies of sinners are called sepulchres of the dead, because the sinner’s soul is dead in his body; for that cannot be deemed to be alive, which does no spiritual or living act. (Saint Thomas Aquinas, citing Pseudo-Chrysostom, in the Catena Aurea, Matthew 23: 27-28)

Venial sin does not preclude every act of grace whereby all venial sins can be removed; whereas mortal sin excludes altogether the habit of grace […] (Saint Thomas Aquinas. Summa Theologica, III, q. 87, a. 4)

First of all, because they destroy the soul: ‘He who is an adulterer has no sense, for the folly of his heart shall destroy his own soul’ (Prov 6:32). It says: ‘for the folly of his heart,’ which is whenever the flesh dominates the spirit. (Saint Thomas Aquinas. The Ten Commandments, Article 8)

Do all the children of the Church share in this communion of goods?
All Christians who are in the grace of God share in the communion of internal goods, while those who are in mortal sin do not participate in these goods.
Why do not those who are in mortal sin participate in these goods?
Because that which unites the faithful with God, and with Jesus Christ as His living members, rendering them capable of performing meritorious works for life eternal, is the grace of God which is the supernatural life of the soul; and hence as those who are in mortal sin are without the grace of God, they are excluded from perfect communion in spiritual goods, nor can they accomplish works meritorious towards life eternal. (Catechism of Saint Pius X, The Communion of Saints, no. 4-5)Sin has a twofold consequence

John Paul II

Likewise, care will have to be taken not to reduce mortal sin to an act of ‘fundamental option’ -as is commonly said today- against God, intending thereby an explicit and formal contempt for God or neighbor. For mortal sin exists also when a person knowingly and willingly, for whatever reason, chooses something gravely disordered. In fact, such a choice already includes contempt for the divine law, a rejection of God's love for humanity and the whole of creation; the person turns away from God and loses charity. (John Paul II. Apostolic Exhortation Reconciliatio et paenitentia, no. 17, December 2, 1984)

Because it offends the holiness and justice of God and scorns God’s personal friendship with man, sin has a twofold consequence. In the first place, if it is grave, it involves deprivation of communion with God and, in consequence, exclusion from a share in eternal life. […] In the second place, “every sin, even venial, entails an unhealthy attachment to creatures, which must be purified either here on earth, or after death in the state called Purgatory. This purification frees one from what is called the “temporal punishment” of sin”, and this expiation removes whatever impedes full communion with God and with one’s brothers and sisters. (John Paul II. Incarnationis mysterium, Bull of Indiction of the Great Jubilee of the Year 2000, no. 10, November 29, 1998)

The advantages of so many and such exalted blessings bestowed by Almighty God are enjoyed by those who lead a Christian life in charity, and are just and beloved of God. As to the dead members; that is, those who are bound in the thralldom of sin and estranged from the grace of God, they are not so deprived of these advantages as to cease to be members of this body; but since they are dead members, they do not share in the spiritual fruit which is communicated to the just and pious. (Catechism of Trent, Article IX, Second Part)

Mortal sin is a radical possibility of human freedom, as is love itself. It results in the loss of charity and the privation of sanctifying grace, that is, of the state of grace. If it is not redeemed by repentance and God’s forgiveness, it causes exclusion from Christ’s kingdom and the eternal death of hell, for our freedom has the power to make choices for ever, with no turning back. (Catechism of the Catholic Church, no. 1861)

What is the first and best disposition to render our prayers efficacious?
The first and best disposition to render our prayers efficacious is to be in the state of grace; or if we are not in that state, to desire to put ourselves in it. (Catechism of Saint Pius X, Prayer, no. 14)

Neither prayer nor any other virtuous act is meritorious without sanctifying grace. And yet even that prayer which impetrates sanctifying grace proceeds from some grace, as from a gratuitous gift, since the very act of praying is ‘a gift of God,’ as Augustine states (De Persever. xxiii). (Saint Thomas Aquinas. Summa Theologica, II-II, q. 83, a. 15)

Where does prayer come from? Whether prayer is expressed in words or gestures, it is the whole man who prays. But in naming the source of prayer, Scripture speaks sometimes of the soul or the spirit, but most often of the heart (more than a thousand times). According to Scripture, it is the heart that prays. If our heart is far from God, the words of prayer are in vain. […]Sin has a twofold consequence
Christian prayer is a covenant relationship between God and man in Christ. It is the action of God and of man, springing forth from both the Holy Spirit and ourselves, wholly directed to the Father, in union with the human will of the Son of God made man. (Catechism of the Catholic Church, nos. 2562. 2564)

A series of critical objections against the doctrine and praxis of the Church pertain to questions of a pastoral nature. Some say, for example, that the language used in the ecclesial documents is too legalistic, that the rigidity of law prevails over an understanding of dramatic human situations. They claim that the human person of today is no longer able to understand such language, that Jesus would have had an open ear for the needs of people, particularly for those on the margins of society. They say that the Church, on the other hand, presents herself like a judge who excludes wounded people from the sacraments and from certain public responsibilities. One can readily admit that the Magisterium’s manner of expression does not seem very easy to understand at times. It needs to be translated by preachers and catechists into a language which relates to people and to their respective cultural environments. The essential content of the Church’s teaching, however, must be upheld in this process. It must not be watered down on allegedly pastoral grounds, because it communicates the revealed truth. Certainly, it is difficult to make the demands of the Gospel understandable to secularized people. But this pastoral difficulty must not lead to compromises with the truth. In his Encyclical Veritatis splendor, John Paul II clearly rejected so-called pastoral solutions which stand in opposition to the statements of the Magisterium (cf. ibid. 56). Furthermore, concerning the position of the Magisterium as regards the question of divorced and remarried members of the faithful, it must be stressed that the more recent documents of the Church bring together the demands of truth with those of love in a very balanced way. If at times in the past, love shone forth too little in the explanation of the truth, so today the danger is great that in the name of love, truth is either to be silenced or compromised. Assuredly, the word of truth can be painful and uncomfortable. But it is the way to holiness, to peace, and to inner freedom. A pastoral approach which truly wants to help the people concerned must always be grounded in the truth. In the end, only the truth can be pastoral. “Then you will know the truth, and the truth will set you free” (Jn. 8:32). (Congregation for the Doctrine of the Faith, Concerning some objections to the Church’s teaching on the reception of Holy Communion, Introduction of Cardinal Joseph Ratzinger, no. 5, January 1, 1998)

There are increasing cases of Catholics who for ideological or practical reasons, prefer to contract a merely civil marriage, and who reject or at least defer religious marriage. Their situation cannot of course be likened to that of people simply living together without any bond at all, because in the present case there is at least a certain commitment to a properly-defined and probably stable state of life, even though the possibility of a future divorce is often present in the minds of those entering a civil marriage. By seeking public recognition of their bond on the part of the State, such couples show that they are ready to accept not only its advantages but also its obligations. Nevertheless, not even this situation is acceptable to the Church. The aim of pastoral action will be to make these people understand the need for consistency between their choice of life and the faith that they profess, and to try to do everything possible to induce them to regularize their situation in the light of Christian principle. While treating them with great charity and bringing them into the life of the respective communities, the pastors of the Church will regrettably not be able to admit them to the sacraments. (John Paul II. Apostolic Exhortation Familiaris consortio, no. 82, November 22, 1981)

For the disease is not palsy only, but also our sin; and this more than that, by how much a soul is better than a body. Let us therefore now also draw nigh unto Him; let us entreat Him that He would brace our paralyzed soul, and leaving all things that pertain to this life, let us take account of the things spiritual only. Or if thou cleave unto these also, yet think of them after the other. Neither must thou think lightly of it, because thou hast no pain in sinning; rather on this very account most of all do thou lament, that thou feelest not the anguish of thine offenses. For not because sin bites not, doth this come to pass, but because the offending soul is insensible. Regard with this view them that have a feeling of their own sins, how they wail more bitterly than such as are being cut, or burned; how many things they do, how many suffer, how greatly they mourn and lament, in order to be delivered from their evil conscience. They would not do any such thing, unless they were exceedingly pained in soul. The best thing then is, to avoid sin in the first instance: the next to it, is to feel that we sin, and thoroughly amend ourselves. But if we have not this, how shall we pray to God, and ask forgiveness of our sins, we who take no account of these matters? For when thou thyself who hast offended art unwilling to know so much as this very fact, that thou hast sinned; for what manner of offenses will thou entreat God for pardon? For what thou knowest not? And how wilt thou know the greatness of the benefit? […] and how shall we by this very thing fail to provoke Him so much the more? For not so much sinning, as sinning without even pain, causes in Him indignation and wrath. (Saint John Chrysostom. Homily 14 on the Gospel of Saint Matthew)

Knowing this, then, let us also not intermit to do all things unto them that sin and are remiss, warning, teaching, exhorting, admonishing, advising, though we profit nothing. For Christ indeed foreknew that the traitor was incorrigible, yet nevertheless He ceased not to supply what could be done by Himself, as well admonishing as threatening and bewailing over him. (Saint John Chrysostom. Homily 80 on the Gospel of Saint Matthew)

But, like a vessel that has lost its rudder is tossed at the mercy of the storm, so man, when by sin he has forfeited the aid of Divine grace, no longer acts as he wills, but as the Devil wills. And if God, by the mighty arm of His mercy, do not loose him, he will abide till death in the chain of his sins. Therefore He saith to His disciples, ‘Loose them,’ that is, by your teaching and miracles, for all the Jews and Gentiles were loosed by the Apostles; ‘and bring them to me,’ that is, convert them to My glory.(Saint Thomas Aquinas, citing Pseudo-Chrysostom, in the Catena Aurea Mt 21:1-9)

Catholic doctrine tells us that the primary duty of charity does not lie in the toleration of false ideas, however sincere they may be, nor in the theoretical or practical indifference towards the errors and vices in which we see our brethren plunged, but in the zeal for their intellectual and moral improvement as well as for their material well-being. Catholic doctrine further tells us that love for our neighbor flows from our love for God, Who is Father to all, and goal of the whole human family; and in Jesus Christ whose members we are, to the point that in doing good to others we are doing good to Jesus Christ Himself. (Pius X. Encyclical Notre Charge Apostolique, no. 22, August 15, 1910)

Another way to do harm is that of those who speak of religious matters as if they were to be considered according to the norms and convenience of this passing life, forgetting the eternal life to come: they speak brilliantly of the benefits that the Christian religion has bequeathed to humanity, but not of the obligations it demands; they preach the charity of Jesus Christ our Savior, but say nothing of his justice. The fruit that such preaching produces is insignificant, because any worldling who hears it becomes convinced that he is a good Christian, and that he has no need to change his life, as long as he says: I believe in Jesus Christ.
What kind of fruits do such preachers expect to reap? They certainly have no intention other than that of gaining at any cost the favor of their listeners, flattering them, and, as long as they see the church full, they do not care if the souls of the faithful remain empty. Consequently, they do not even mention sin, the four last things, or any other important topic. Rather, to obtain acclaim and applause, they use complacent language, with eloquence more fitting for worldly speeches than an apostolic and sacred sermon. Against such preachers, Saint Jerome wrote (Ad Nep.): ‘When you teach in the church, you should not merely provoke the acclamation of the congregation, but rather, compunction: the tears of your listeners should be your praise.’ (Pius X. Motu Proprio Sacrorum antistitum, September 1, 1910)

Venerable Brethren, how mistaken are those who think they are doing service to the Church, and producing fruit for the salvation of souls, when by a kind of prudence of the flesh […] under the fatal illusion that they are thus able more easily to win over those in error, but really with the continual danger of being themselves lost. The truth is one, and it cannot be halved; it lasts forever, and is not subject to the vicissitudes of the times. ‘Jesus Christ, today and yesterday, and the same for ever’ (Heb 13: 8). (Pius X. Encyclical Iucunda sane, no. 25-26, March 12, 1904)

It behooves Us, too, Us especially, to inculcate that other saying so noble and so paternal of Anselm: ‘Whenever I hear anything of you displeasing to God and unbecoming to yourselves, and fail to admonish you, I do not fear God nor love you as I ought’ […] then, We should imitate Anselm by renewing Our prayers, counsels, admonitions ‘that you think over these things carefully and if your conscience warns you that there is something to be corrected in them that you hasten to make the correction’ (Epist., lib. iv. epist. 32). For nothing is to be neglected that can be corrected, since God demands an account from all not only of the evil they do but also of the correction of evil which they can correct. And the more power men have to make the necessary correction the more vigorously does He require them, according to the power mercifully communicated to them, to think and act rightly . . . (Pius X. Encyclical Communium rerum, no. 26, April 21, 1909)

The Gospel text […] tells us that brotherly love also involves a sense of mutual responsibility. For this reason if my brother commits a sin against me I must treat him charitably and first of all, speak to him privately, pointing out that what he has said or done is wrong. This approach is known as ‘fraternal correction’: it is not a reaction to the offence suffered but is motivated by love for one’s brethren. St Augustine comments: ‘Whoever has offended you, in offending you, has inflicted a serious injury upon himself; and would you not care for a brother’s injury?…You must forget the offence you have received but not the injury of one of your brethren (Discourse 82, 7). And what if my brother does not listen to me? In today’s Gospel Jesus points to a gradual approach: first, speak to him again with two or three others, the better to help him realize what he has done; if, in spite of this, he still refuses to listen, it is necessary to tell the community; and if he refuses to listen even to the community, he must be made to perceive that he has cut himself off by separating himself from the communion of the Church. All this demonstrates that we are responsible for each other in the journey of Christian life; each person, aware of his own limitations and shortcomings, is called to accept fraternal correction and to help others with this specific service. (Benedict XVI. Angelus, September 4, 2011)

The Scriptures tell us: ‘Rebuke the wise and he will love you for it. Be open with the wise, he grows wiser still, teach the upright, he will gain yet more’ (Prov 9:8ff). Christ himself commands us to admonish a brother who is committing a sin (cf. Mt 18:15). The verb used to express fraternal correction – elenchein – is the same used to indicate the prophetic mission of Christians to speak out against a generation indulging in evil (cf. Eph 5:11). The Church’s tradition has included ‘admonishing sinners’ among the spiritual works of mercy. It is important to recover this dimension of Christian charity. We must not remain silent before evil. I am thinking of all those Christians who, out of human regard or purely personal convenience, adapt to the prevailing mentality, rather than warning their brothers and sisters against ways of thinking and acting that are contrary to the truth and that do not follow the path of goodness. Christian admonishment, for its part, is never motivated by a spirit of accusation or recrimination. It is always moved by love and mercy, and springs from genuine concern for the good of the other. As the Apostle Paul says: ‘If one of you is caught doing something wrong, those of you who are spiritual should set that person right in a spirit of gentleness; and watch yourselves that you are not put to the test in the same way’ (Gal 6:1). In a world pervaded by individualism, it is essential to rediscover the importance of fraternal correction, so that together we may journey towards holiness. […]The Apostle Paul encourages us to seek ‘the ways which lead to peace and the ways in which we can support one another’ (Rom 14:19) for our neighbour’s good, ‘so that we support one another’ (15:2), seeking not personal gain but rather ‘the advantage of everybody else, so that they may be saved’ (1 Cor 10:33). This mutual correction and encouragement in a spirit of humility and charity must be part of the life of the Christian community. (Benedict XVI. Message for Lent 2012, no. 1-3, November 3, 2011)

The correction of the wrongdoer is a remedy which should be employed against a man’s sin. Now a man’s sin may be considered in two ways, first as being harmful to the sinner, secondly as conducing to the harm of others, by hurting or scandalizing them, or by being detrimental to the common good, the justice of which is disturbed by that man’s sin, Consequently the correction of a wrongdoer is twofold, one which applies a remedy to the sin considered as an evil of the sinner himself. This is fraternal correction properly so called, which is directed to the amendment of the sinner. Now to do away with anyone’s evil is the same as to procure his good: and to procure a person’s good is an act of charity, whereby we wish and do our friend well. Consequently fraternal correction also is an act of charity, because thereby we drive out our brother’s evil, viz. sin, the removal of which pertains to charity rather than the removal of an external loss, or of a bodily injury, in so much as the contrary good of virtue is more akin to charity than the good of the body or of external things. Therefore fraternal correction is an act of charity rather than the healing of a bodily infirmity, or the relieving of an external bodily need. There is another correction which applies a remedy to the sin of the wrongdoer, considered as hurtful to others, and especially to the common good. This correction is an act of justice, whose concern it is to safeguard the rectitude of justice between one man and another. (Saint Thomas Aquinas. Summa Theologica, II-II. q. 33, a.1)

The good physician removes the external symptoms of a malady; and, furthermore, he even removes the very root of the illness, so that there will be no relapse. So also the Lord wishes us to avoid the beginnings of sins […]. (Saint Thomas Aquinas. The Ten Commandments, Article 7)

Secondly, they deprive one of life; for one guilty of such should die according to the Law, as we read in Leviticus (20:10) and Deuteronomy (22:22). Sometimes the guilty one is not punished now bodily, which is to his disadvantage since punishment of the body may be borne with patience and is conducive to the remission of sins; but nevertheless he shall be punished in the future life. (Saint Thomas Aquinas. The Ten Commandments, Article 8)

For as in bodily diseases there are many of which the affected are not sensible, but they rather put faith in the opinion of their physicians, than trust their own insensibility; so also in the diseases of the soul, though a man is not conscious of sin in himself, yet ought he to trust to those who are able to have more knowledge of their own sins. (Saint Basil the Great cited by Saint Thomas Aquinas. Catena Aurea in Lk 22:21-23)

St. John M. Vianney always had ‘poor sinners,’ as he called them, in his mind and before his eyes, with the constant hope of seeing them turn back to God and weep for the sins they had committed. This was the object of all his thoughts and cares, and of the work that took up almost all his time and efforts. From his experience in the tribunal of Penance, in which he loosed the bonds of sin, he understood just how much malice there is in sin and what terrible devastation it wreaks in the souls of men. He used to paint it in hideous colors: ‘If we’—he asserted—‘had the faith to see a soul in mortal sin, we would die of fright.’ (John XXIII. Encyclical Sacerdotii nostri primordia, no. 90-91, August 1, 1950)

Lent encourages believers to take seriously Jesus’ exhortation: ‘Enter by the narrow gate; for the gate is wide and the way is easy, that leads to destruction, and those who enter by it are many’ (Mt 7:13). What is this ‘wide gate’ and ‘easy way’ that Jesus refers to? It is the gate of moral self-sufficiency; the way of intellectual pride. How many people, even amongst Christians, live indifferently and accommodate themselves to a worldly mentality and to the gratification of sin! Lent is an appropriate time to analyze one’s own life, in order to renew with greater decisiveness our participation in the sacraments, to make firmer resolutions for a new life, endeavoring, as Jesus taught, to pass through the narrow gate and difficult way that leads to eternal life (cf. Mt 7:14). (John Paul II. General Audience, no. 3, February 16, 1994)

The expiatory sacrifice of the cross makes us understand the gravity of sin. In the eyes of God, sin is never without importance. The Father loves mankind, and is profoundly offended by their transgressions or rebellions. Even though he is disposed to pardon, He, for the good and honor of man himself, requires reparation. But it is precisely here that the divine generosity is shown in a more surprising manner. The Father gives to humanity His own Son to offer this reparation. With this he shows the abysmal gravity of sin, since it requires the highest reparation possible, that which comes from His own Son. At the same time, it reveals the infinite grandeur of his love, since He is the first, with the gift of his Son, that carries the weight of the reparation. (John Paul II. General Audience, no. 2, April 20, 1983)

To avoid any misunderstanding, it should be noted that Jesus’ mercy was not expressed by putting moral law in parentheses. For Jesus, good is good and evil is evil. Mercy does not change the connotations of sin but consumes it in a fire of love. This purifying and healing effect is achieved if within the person there is a corresponding love which implies recognition of God’s law, sincere repentance and the resolution to start a new life. The sinful woman in the Gospel was pardoned greatly because she loved greatly. In Jesus, God comes to give love to us and to ask love of us. (Benedict XVI. Homily during the Pastoral Visit to Assisi on the Eighth Centenary of the Conversion of Saint Francis, June 17, 2007)

‘Neither do I condemn you;’ by whom, perhaps, you feared to be condemned, because in me you have not found sin. ‘Neither will I condemn you.’ What is this, O Lord? Do You therefore favor sins? Not so, evidently. Mark what follows: ‘Go, henceforth sin no more.’ Therefore the Lord did also condemn, but condemned sins, not man. For if He were a patron of sin, He would say, Neither will I condemn you; go, live as you will: be secure in my deliverance; how much soever you will sin, I will deliver you from all punishment even of hell, and from the tormentors of the infernal world. He said not this. (Saint Augustine of Hippo. Tractates on the Gospel of St. John, 33, 6)

And most suitable is such a similitude, so that spiritually there may be seen to be as great a difference between the righteous and sinners, as there is materially between heaven and earth. (Saint Augustine of Hippo. Sermon on the Mount, Book II, Ch. 5, no. 17)

Therefore we ought to love some neighbors more than others? […] Our neighbors are not all equally related to God; some are nearer to Him, by reason of their greater goodness, and those we ought, out of charity, to love more than those who are not so near to Him. (Saint Thomas Aquinas. Summa Theologica, II-II, q. 26, a. 6)

Further, whilst Jesus was kind to sinners and to those who went astray, He did not respect their false ideas, however sincere they might have appeared. He loved them all, but He instructed them in order to convert them and save them. Whilst He called to Himself in order to comfort them, those who toiled and suffered, it was not to preach to them the jealousy of a chimerical equality. Whilst He lifted up the lowly, it was not to instill in them the sentiment of a dignity independent from, and rebellious against, the duty of obedience. Whilst His heart overflowed with gentleness for the souls of good-will, He could also arm Himself with holy indignation against the profaners of the House of God, against the wretched men who scandalized the little ones, against the authorities who crush the people with the weight of heavy burdens without putting out a hand to lift them. He was as strong as he was gentle. He reproved, threatened, chastised, knowing, and teaching us that fear is the beginning of wisdom, and that it is sometimes proper for a man to cut off an offending limb to save his body. (Pius X. Encyclical Notre Charge Apostolique, August 15, 1910)

There are other ecclesial functions, that presuppose a testimony of exacting Christian life, that also may not be held by the divorced who have undergone another civil marriage: liturgical service (lector, extraordinary Eucharistic minister), Catechetical service (religion teacher, catechist for first communion or confirmation), participation as a member of the diocesan pastoral or parochial council. The members of these councils should be fully inserted into the ecclesial and sacramental life, and lead, moreover, a life that is in accordance with the moral principles of the Church. Canon Law establishes that, for pastoral and diocesan council, – and this is true also for the parochial Councils – that ‘No one except members of the Christian faithful outstanding in firm faith, good morals, and prudence is to be designated to a pastoral council’ (CIC, can. 512, §3). (Congregation for the Doctrine of the Faith. Concerning some objections to the Church’s teaching on the reception of Holy Communion, Introduction of Cardinal Joseph Ratzinger, January 1, 1998)

This view contradicts Catholic teaching that excludes the possibility of remarriage after divorce: ‘Today there are numerous Catholics in many countries who have recourse to civil divorce and contract new civil unions. In fidelity to the words of Jesus Christ – ‘Whoever divorces his wife and marries another, commits adultery against her; and if she divorces her husband and marries another, she commits adultery’ (Mk 10:11-12) –, the Church maintains that a new union cannot be recognized as valid, if the first marriage was. If the divorced are remarried civilly, they find themselves in a situation that objectively contravenes God’s law. Consequently, they cannot receive Eucharistic communion as long as this situation persists. For the same reason, they cannot exercise certain ecclesial responsibilities. Reconciliation through the sacrament of Penance can be granted only to those who have repented for having violated the sign of the covenant and of fidelity to Christ, and who are committed to living in complete continence’(Catechism of the Catholic Church, n. 1650). (Congregation for the Doctrine of the Faith. Notification on the book ‘Just Love’. A framework for Christian Sexual Ethics by Sr. Margaret A. Farley, R.S.M, March 30, 2012)

Those who lack or do not practice the interior virtues […] may not be considered sufficiently prepared or armed against the dangers and battles of life, nor able to dedicate themselves to the apostolate; rather, just as a ‘a noisy gong or a clanging cymbal’ (1 Cor 13,1), they either do not benefit an any way, or perhaps even damage the very cause which they seek to sustain and defend, as has notoriously occurred, and not on only one occasion, in the past. (Pius XI. Apostolic Letter Singulare illud, June 13, 1926)

Therefore, all who are called upon to direct or dedicate themselves to the Catholic cause, must be sound Catholics, firm in faith, solidly instructed in religious matters, truly submissive to the Church and especially to this supreme Apostolic See and the Vicar of Jesus Christ. They must be men of real piety, of manly virtue, and of a life so chaste and fearless that they will be a guiding example to all others. If they are not so formed it will be difficult to arouse others to do good and practically impossible to act with a good intention. (Pius X. Encyclical Il fermo proposito, no. 11, June 11, 1905)

Men will not believe in Christ and will not take His Gospel seriously if they do not find signs of his presence. Especially today there is a necessity of finding him and of somehow seeing him. ‘The men and women of our own day – John Paul II observed – often perhaps unconsciously, ask believers not only to ‘speak’ of Christ, but in a certain sense to ‘show’ him’ (Novo Millennio Ineunte, 16). Christ can be seen in miracles; but even more so he can be seen in the saints, not only in those heroic and extraordinary saints, but also in the ordinary saints who tend toward sanctity as a ‘high standard of ordinary Christian living’ (NMI, 31) and are not content with ‘a life of mediocrity, marked by a minimalist ethic and a shallow religiosity’ (ibid.). Today, more than ever, there is a lack of exemplary Christians, of united Christian families, of feverous ecclesial communities. To resolve the crisis of the family – which is a crisis of matrimony, of natality and education, that results in the disunion and exhaustion of society – the most important pastoral mission is to form in each parish groups of families that are a living gospel. To evangelize our secularized world and the people that ignore our faith, the authenticity of the Christian life is more necessary than the number of Christians. It is though a few that many are challenged, and can orient themselves toward eternal life, even though on this earth they do not arrive at being fully inserted in the Church. What is more important is that there exist lit fires to enlighten and warm the night. (Pontifical Council for the Family. Homily of Cardinal Ennio Antonelli at the Closing Mass of the Help the Family Today Congress, December 12, 2010)

Today more than ever the witness and public commitment of all the baptized is necessary to reaffirm the dignity and the unique, irreplaceable value of the family founded on the marriage of a man and a woman open to life, and also of human life in all of its stages. Legal and administrative measures must be promoted that support families with their inalienable rights, necessary if they are to continue to carry out their extraordinary mission. The witnesses given at yesterday’s celebration show that today too the family can stand firm in the love of God and renew humanity in the new millennium. I wish to express my closeness and to assure my prayers for all the families that bear witness to fidelity in especially difficult circumstances. I encourage the many families who, at times living in the midst of setbacks and misunderstandings, set an example of generosity and trust in God, in the hope that they will not lack the assistance they need. I am also thinking of the families who are suffering because of poverty, sickness, marginalization or emigration and, most especially, of Christian families that are being persecuted for their faith. The Pope is very close to all of you and accompanies you in your daily efforts. (Benedict XVI. Address at the Closing Mass of the Sixth World Day of Families held in Mexico City, January 18, 2009)

But you, brothers, do not be remiss in doing good. If anyone does not obey our word as expressed in this letter, take note of this person not to associate with him, that he may be put to shame. Do not regard him as an enemy but admonish him as a brother. (2 Thes 3:13-15)

So also with the woman who is unfaithful to her husband and offers as heir her son by a stranger. First, she has disobeyed the law of the Most High; secondly, she has wronged her husband; Thirdly, in her wanton adultery she has borne children by another man. Such a woman will be dragged before the assembly, and her punishment will extend to her children; Her children will not take root; her branches will not bring forth fruit. She will leave an accursed memory; her disgrace will never be blotted out. Thus all who dwell on the earth shall know, and all who inhabit the world shall understand, That nothing is better than the fear of the Lord, nothing more salutary than to obey his commandments. (Sir 23:22-27)

To carry it out right one must have divine grace, and the apostle receives it only if he is united to Christ. Only when he has formed Jesus Christ in himself shall he more easily be able to restore Him to the family and society. Therefore, all who are called upon to direct or dedicate themselves to the Catholic cause, must be sound Catholics, firm in faith, solidly instructed in religious matters, truly submissive to the Church and especially to this supreme Apostolic See and the Vicar of Jesus Christ. They must be men of real piety, of manly virtue, and of a life so chaste and fearless that they will be a guiding example to all others. (Pius X. Encyclical Il fermo proposito, no. 11, June 11, 1905)

Is not a confessor too severe, who defers absolution because he does not believe the penitent is well enough disposed?
A confessor who defers absolution because he does not believe the penitent well enough disposed, is not too severe; on the contrary, he is very charitable and acts as a good physician who tries all remedies, even those that are disagreeable and painful, to save the life of his patient. (Catechism of Saint Pius X, The Sacrament of Penance, no. 102)

Between the customs of a secularized society and the requirements of the Gospel, a profound rift is being created. There are many who wish to participate in ecclesial life, but do not find any relation between the world in which they live and Christian principles. It is believed that the Church, merely due to rigidity, adheres firmly to its norms; and that this contrasts with the mercy that Jesus gives us the example in the Gospel. The difficult demands of Jesus, his words: ‘Go and from now on do not sin anymore’ (Jn 8:11), are ignored. Often, we fall back on personal conscience, forgetting however, that this conscience is as an eye that does not possess light in itself, but only when it looks toward the authentic source of light. (John Paul II. Allocution to the German Episcopal Conference, no. 6, November 17, 1980)

This same declaration does Esaias make: ‘To what purpose is the multitude of your sacrifices unto Me? saith the Lord. I am full.’(Is 1:10) And when He had repudiated holocausts, and sacrifices, and oblations, as likewise the new moons, and the sabbaths, and the festivals, and all the rest of the services accompanying these, He continues, exhorting them to what pertained to salvation: ‘Wash you, make you clean, take away wickedness from your hearts from before mine eyes: cease from your evil ways, learn to do well, seek judgment, relieve the oppressed, judge the fatherless, plead for the widow; and come, let us reason together, saith the Lord.’ […] But inasmuch as God is merciful, He did not cut them off from good counsel. For after He had said by Jeremiah, ‘To what purpose bring ye Me incense from Saba, and cinnamon from a far country? Your whole burnt-offerings and sacrifices are not acceptable to Me;’ He proceeds: ‘Hear the word of the Lord, all Judah. These things saith the Lord, the God of Israel, Make straight your ways and your doings, and I will establish you in this place. Put not your trust in lying words, for they will not at all profit you, saying, The temple of the Lord, The temple of the lord, it is (here).’ (Saint Irenaeus of Lyons. Against Heresies, Book 4, Ch. 17, no. 1-2)