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 9:8). Christ himself commands us to admonish a brother who is committing a sin (cf. Mt 18:15). 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. […] 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’ (Rom 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, November 3, 2011)

St Augustine in his Commentary observed:  ‘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; however much you sin, I will deliver you from all punishment’. He said not this (Io Ev. tract. 33, 6). […] Therefore, we understand that our real enemy is attachment to sin, which can lead us to failure in our lives. Jesus sent the adulterous woman away with this recommendation:  ‘Go, and do not sin again’. He forgives her so that ‘from now on’ she will sin no more. (Benedict XVI. Visit to the Roman Parish of Saint Felicity and her Children, Martyrs, March 25, 2007)

Saint Luke remarks first of all that the people ‘were in expectation’ (Lk 3: 15). In this way he emphasizes the expectation of Israel and, in those people who had left their homes and their usual tasks, the profound desire for a different world and new words that seem to find an answer precisely in the Precursor’s words that may be severe and demanding and yet are full of hope. The baptism John offers is one of repentance, a sign that is an invitation to conversion, to a change of life, because One is coming who will ‘baptize with the Holy Spirit and with fire’ (Lk 3:16). Indeed it is impossible to aspire to a new world while remaining immersed in selfishness and habits linked to sin. (Benedict XVI. Homily on the Feast of the Baptism of the Lord, January 10, 2010)

Commit yourselves with all your strength to assuring that the unchanging criteria and norms of Christian action become valid in a clear and persuasive manner in the life of the believer. There is a profound abyss between the costumes of a secularized society and the demands of the Gospel. Many are those who wish to participate in ecclesial life, but find no relation between their world and Christian principles. They believe that it is due to a kind of rigidity that the Church maintains its norms, and that this conflicts with the mercy Jesus taught us in the Gospel. Jesus’ firm demands, his words: ‘Go, and do not sin again’ (Jn 8: 11), are ignored. Trusting one’s personal conscience is often spoken of, forgetting, however, that this conscience is like eye that does not possess light in itself, but only when it gazes toward its true source. (John Paul II. Allocution to the Episcopal Conference of Germany, no. 6, November 17, 1980)

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)

Before the consciences of the faithful, who open up to him with a mixture of fear and trust, the confessor is called to a lofty task which is one of service for penance and human reconciliation. It is a task of understanding the weaknesses and falls of the faithful, assessing their desire for renewal and their efforts to achieve it, discerning the action of the Holy Spirit in their hearts, imparting to them a forgiveness which God alone can grant, ‘celebrating’ their reconciliation with the Father, portrayed in the parable of the prodigal son, reinstating these redeemed sinners in the ecclesial community with their brothers and sisters, and paternally admonishing these penitents with a firm, encouraging and friendly ‘Do not sin again.’ (John Paul II, Apostolic Exhortation Reconciliatio et paenitentia, December 2, 1984)

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)

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: may the tears of your listeners should be your praise.’ (Pius X. Motu Proprio Sacrorum antistitum, September 1, 1910)

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 the love for God, Who is Father to all and the goal of the whole human family, and for 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)

For, while 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 who scandalize 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 often fear is the beginning of wisdom, and that it sometimes is fitting to cut off a limb to save the body. (Pius X. Encyclical Notre charge apostolique, no. 38, August 15, 1910)

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).
And so too are all they seriously mistaken who, occupying themselves with the welfare of the people, and especially upholding the cause of the lower classes, seek to promote above all else the material well-being of the body and of life, but are utterly silent about their spiritual welfare and the very serious duties which their profession as Christians enjoins upon them. They are not ashamed to conceal sometimes, as though with a veil, certain fundamental maxims of the Gospel, for fear lest otherwise the people refuse to hear and follow them. (Pius X. Encyclical Iucunda sane, no. 25, 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.’ […] 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, April 21, 1909)

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)

Salt must certainly be mingled with the mass which it is to preserve from corruption, but it must at the same time defend itself against the mass under pain of losing all savor and becoming of no use except to be thrown out and trampled underfoot. (Mt 5:13) (Leo XIII. Encyclical Depuis le Jour, no. 38, September 8, 1899)

This conformation to Christ is the very substance of sanctification and is the specific goal of all Christian life. In order to accomplish this objective, all Christians need the Church’s assistance, since she is both mater et magistra. The pedagogy of holiness is a goal which is as attractive as it is challenging for all those in the Church who hold responsibilities of government and formation. […] In contemporary society, which is marked by cultural, religious and ethnic pluralism, relativism, indifferentism, irenicism, and syncretism, it appears that some Christians have become accustomed to a form of ‘Christianity’ lacking any real reference to Christ and his Church. In these circumstances, the pastoral mission is reduced to social concerns which are envisaged in exclusively anthropological terms, often based on a vague appeal to pacificism, universalism or to a loose reference to ‘values’. (Congregation for the Clergy. The Priest, Pastor and Leader of the Parish Community, no. 28-29, November 23, 2001)

Should anyone desire Baptism and be unwilling to correct the habit of sinning, he should be altogether rejected. For nothing is so opposed to the grace and power of Baptism as the intention and purpose of those who resolve never to abandon sin.
Seeing that Baptism should be sought with a view to put on Christ and to be united to Him, it is manifest that he who purposes to continue in sin should justly be repelled from the sacred font, particularly since none of those things which belong to Christ and His Church are to be received in vain and since we well understand that, as far as regards sanctifying and saving grace, Baptism is received in vain by him who purposes to live according to the flesh, and not according to the spirit. (Catechism of Trent. Part II, Chapter 1, VIII, C-3)

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 LXXX on the Gospel of Saint Matthew)

This same declaration does Isaias make: ‘To what purpose is the multitude of your sacrifices unto Me? Says the Lord, I am full’ (Is 1:11). 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 my 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, says 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 did you bring Me incense from Saba, and cinnamon from a far country? Your whole burnt-offerings and sacrifices are not acceptable to Me’ (Jer 6:20). He proceeds: ‘Hear the word of the Lord, all Judah. These things says 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’ (Jer 7:2-3). (Saint Irenaeus of Lyons. Adversus Haereses, Book IV, Ch. 17)

Neither will I condemn you. What is this, O Lord? Do thou 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 John, Tractate 33, 6)

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)

If you do good, know for whom you are doing it, and your kindness will have its effect. Do good to the just man and reward will be yours, if not from him, from the Lord. No good comes to him who gives comfort to the wicked, nor is it an act of mercy that he does. Give to the good man, refuse the sinner; refresh the downtrodden, give nothing to the proud man. No arms for combat should you give him, lest he use them against yourself; with twofold evil you will meet for every good deed you do for him. The Most High himself hates sinners, and upon the wicked he takes vengeance. (Sir 12:1-7)