True, Jesus has loved us with an immense, infinite love, and He came on earth to suffer and die so that, gathered around Him in justice and love, motivated by the same sentiments of mutual charity, all men might live in peace and happiness. But for the realization of this temporal and eternal happiness, He has laid down with supreme authority the condition that we must belong to His Flock, that we must accept His doctrine, that we must practice virtue, and that we must accept the teaching and guidance of Peter and his successors. 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. […] These are teachings that it would be wrong to apply only to one’s personal life in order to win eternal salvation; these are eminently social teachings, and they show in Our Lord Jesus Christ something quite different from an inconsistent and impotent humanitarianism. (Saint Pius X. Encyclical Notre charge apostolique, August 15, 1910)

And this indeed was the purpose of the merciful Jesus, when He showed His Heart to us bearing about it the symbols of the passion and displaying the flames of love, that from the one we might know the infinite malice of sin, and in the other we might admire the infinite charity of Our Redeemer, and so might have a more vehement hatred of sin, and make a more ardent return of love for His love. (Pius XI. Encyclical Miserentissimus Redemptor, no. 11, May 8, 1928)

Herod was very glad to see Jesus; he had been wanting to see him for a long time, for he had heard about him and had been hoping to see him perform some sign. He questioned him at length, but he gave him no answer. (Lk 23:8-9)

From these words we ought to derive a lesson, that whenever our hearers wish as if by praising us to gain knowledge from us, but not to change their own wicked course, we must be altogether silent, lest if from love of ostentation we speak God’s word, both they who were guilty cease not to be so, and we who were not become so. (Gregory I, the Great, quoted by Saint Thomas Aquinas. Catena Aurea on Lk 23:6-12)

A Pharisee invited him to dine with him, and he entered the Pharisee’s house and reclined at table. Now there was a sinful woman in the city who learned that he was at table in the house of the Pharisee. Bringing an alabaster flask of ointment, she stood behind him at his feet weeping and began to bathe his feet with her tears. Then she wiped them with her hair, kissed them, and anointed them with the ointment. When the Pharisee who had invited him saw this he said to himself, ‘If this man were a prophet, he would know who and what sort of woman this is who is touching him, that she is a sinner.’ Jesus said to him in reply, ‘Simon, I have something to say to you.’ ‘Tell me, teacher,’ he said. ‘Two people were in debt to a certain creditor; one owed five hundred days’ wages and the other owed fifty. Since they were unable to repay the debt, he forgave it for both. Which of them will love him more?’ Simon said in reply, ‘The one, I suppose, whose larger debt was forgiven.’ He said to him, ‘You have judged rightly.’ Then he turned to the woman and said to Simon, ‘Do you see this woman? When I entered your house, you did not give me water for my feet, but she has bathed them with her tears and wiped them with her hair. You did not give me a kiss, but she has not ceased kissing my feet since the time I entered. You did not anoint my head with oil, but she anointed my feet with ointment. So I tell you, her many sins have been forgiven; hence, she has shown great love. But the one to whom little is forgiven, loves little.’ He said to her, ‘Your sins are forgiven.’ The others at table said to themselves, ‘Who is this who even forgives sins?’ But he said to the woman, ‘Your faith has saved you; go in peace.’ (Lk 7:36-50)

Saint Luke, the physician of souls rather than of bodies, represents therefore our Lord and Savior most mercifully visiting others, as it follows, And he went into the Pharisees’ house, and sat down to meat. Not that He should share any of his faults, but might impart somewhat of His own righteousness. (Saint Gregory Nicene quoted by Saint Thomas Aquinas. Catena Aurea on Lk 7:36-50)

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. (Benedict XVI. Homily in Assisi on the eighth centenary of the conversion of Saint Francis, June 17, 2007)

Behold she who had come sick to the Physician was healed, but because of her safety others are still sick; for it follows, And they that sat at meat began to say within themselves, Who is this that forgives sins also. But the heavenly Physician regards not those sick, whom He sees to be made still worse by His remedy, but her whom He had healed He encourages by making mention of her own piety; as it follows, But he said to the woman, Your faith has made you whole; for in truth she doubted not that she would receive what she sought for. (Gregory I, quoted by Saint Thomas Aquinas. Catena Aurea on Lk 7:36-50)

So also some gifted with the priests’ office, if perchance they have done any just thing outwardly or slightly, forthwith despise those who are put under them, and look with disdain on sinners who are of the people. But when we behold sinners, we must first bewail ourselves for their calamity, since we perhaps have had and are certainly liable to a similar fall. But it is necessary that we should carefully distinguish, for we are bound to make distinction in vices, but to have compassion on nature. For if we must punish the sinner, we must cherish a brother. But when by penance he has himself punished his own deed, our brother is no more a sinner, for he punished in himself what Divine justice condemned. The Physician was between two sick persons, but the one preserved her faculties in the fever, the other lost his mental perception. For she wept at what she had done; but the Pharisee, elated with a false sense of righteousness, overrated the vigor of his own health. (Gregory I, quoted by Saint Thomas Aquinas. Catena Aurea on Lk 7:36-50)

But after having forgiven her sins, He stops not at the forgiveness of sins, but adds good works, as it follows, Go in peace, i.e. in righteousness, for righteousness is the reconciliation of man to God, as sin is the enmity between God and man; as if He said, Do all things which lead you to the peace of God. (Theophilus, quoted by Saint Thomas Aquinas. Catena Aurea on Lk 7:36-50)

But early in the morning he arrived again in the temple area, and all the people started coming to him, and he sat down and taught them. Then the scribes and the Pharisees brought a woman who had been caught in adultery and made her stand in the middle. They said to him, ‘Teacher, this woman was caught in the very act of committing adultery. Now in the law, Moses commanded us to stone such women. So what do you say?’ They said this to test him, so that they could have some charge to bring against him. Jesus bent down and began to write on the ground with his finger. But when they continued asking him, he straightened up and said to them, ‘Let the one among you who is without sin be the first to throw a stone at her.’ Again he bent down and wrote on the ground. And in response, they went away one by one, beginning with the elders. So he was left alone with the woman before him. Then Jesus straightened up and said to her, ‘Woman, where are they? Has no one condemned you?’ She replied, ‘No one, sir.’ Then Jesus said, ‘Neither do I condemn you. Go, (and) from now on do not sin anymore.’ (Jn 8:2-11)

But when that woman was left alone, and all they had gone out, He raised His eyes to the woman. […] But He, who had driven back her adversaries with the tongue of justice, raising the eyes of clemency towards her, asked her, ‘Hath no man condemned you?’ She answered, ‘No man, Lord.’ And He said, ‘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. […] The Lord is gentle, the Lord is long-suffering, the Lord is pitiful; but the Lord is also just, the Lord is also true. He bestows on you space for correction; but you love the delay of judgment more than the amendment of your ways. Have you been a bad man yesterday? Today be a good man. Have you gone on in your wickedness today? At any rate change tomorrow. You are always expecting, and from the mercy of God makest exceeding great promises to yourself. As if He, who has promised you pardon through repentance, promised you also a longer life. How do you know what tomorrow may bring forth? Rightly you say in your heart: When I shall have corrected my ways, God will put all my sins away. We cannot deny that God has promised pardon to those that have amended their ways and are converted. For in what prophet you read to me that God has promised pardon to him that amends, you do not read to me that God has promised you a long life. (Saint Augustine of Hippo. Tractate 33 on the Gospel of Saint John, no. 6-7)

Between the customs of a secularized society and the demands of the Gospel, a profound chasm is growing. There are many who would like to participate in ecclesial life, but no longer perceive a connection between the world in which they live and Christian principles. It is believed that the Church adheres firmly to her norms, merely from rigidity and that this clashes with the mercy which Jesus gives us an example in the Gospel. The difficult demands of Jesus, His words: ‘Go, and now sin no more’ (Jn 8, 11) are ignored. Recourse to one’s personal conscience is often spoken of, forgetting, however, that this conscience is like an eye that does not possess light of itself, but rather only when it looks toward the authentic source of light. (John Paul II. Allocution to the Episcopal Conference of Germany in Fulda, no. 6, November 17, 1980)

He came to Jericho and intended to pass through the town. Now a man there named Zacchaeus, who was a chief tax collector and also a wealthy man, was seeking to see who Jesus was; but he could not see him because of the crowd, for he was short in stature. So he ran ahead and climbed a sycamore tree in order to see Jesus, who was about to pass that way. When he reached the place, Jesus looked up and said to him, ‘Zacchaeus, come down quickly, for today I must stay at your house.’ And he came down quickly and received him with joy. When they all saw this, they began to grumble, saying, ‘He has gone to stay at the house of a sinner.’ But Zacchaeus stood there and said to the Lord, ‘Behold, half of my possessions, Lord, I shall give to the poor, and if I have extorted anything from anyone I shall repay it four times over.’ And Jesus said to him, ‘Today salvation has come to this house because this man too is a descendant of Abraham. For the Son of Man has come to seek and to save what was lost.’ (Lk 19:1-10)

Observe the gracious kindness of the Savior. The innocent associates with the guilty, the fountain of justice with covetousness, which is the source of injustice. Having entered the publican’s house, He suffers no stain from the mists of avarice, but disperses them by the bright beam of His righteousness. But those who deal with biting words and reproaches, try to cast a slur upon the things which were done by Him; for it follows, And when they saw it, they all murmured, saying, that he was gone to be guest with a man that is a sinner. But He, though accused of being a wine-bibber and a friend of publicans, regarded it not, so long as He could accomplish His end. As a physician sometimes cannot save his patients from their diseases without the defilement of blood, kind so it happened here, for the publican was converted, and lived a better life. Zacchaeus stood, and said to the Lord, Behold, Lord, the half of my goods I give to the poor; and if I have defrauded any man, I restore him fourfold. Behold here is a marvel: without learning he obeys. And as the sun pouring its rays into a house enlightens it not by word, but by work, so the Savior by the rays of righteousness put to flight the darkness of sin; for the light shines in darkness. (Pseudo-Chrysostom quoted by Saint Thomas Aquinas. Catena Aurea on Lk 19:1-10)

The seed of salvation had begun to spring up in him, for he desired to see Jesus, having never seen Him. For if he had seen Him, he would long since have given up the Publican’s wicked life. No one that sees Jesus can remain any longer in wickedness. But there were two obstacles to his seeing Him. The multitude not so much of men as of his sins prevented him, for he was little of stature. (Titus of Bostra, quoted by Saint Thomas Aquinas. Catena Aurea on Lk 19:1-10)

See here, the camel disencumbered of his hunch passes through the eye of a needle, that is, the rich man and the publican abandoning his love of riches, and loathing his dishonest gains, receives the blessing of his Lord’s company. It follows, and he made haste, and came down, and received him joyfully. (Saint Bede the Venerable quoted by Saint Thomas Aquinas. Catena Aurea on Lk 19:1-10)

The Lord said to him, Make haste and come down, that is, ‘you have ascended by penitence to a place too high for you, come down by humility, lest your exaltation cause you to sky. I must abide in the house of a humble man. We have two kinds of goods in us, bodily, and spiritual; the just man gives up all his bodily goods to the poor, but he forsakes not his spiritual goods, but if he has extorted anything from any one, he restores to him fourfold; signifying thereby that if a man by repentance walks in the Opposite path to his former perverseness, he by the manifold practice of virtue heals all his old offenses, and so merits salvation, and is called the son of Abraham, because he went out from his own kindred, that is, from his ancient wickedness. (Theophilus quoted by Saint Thomas Aquinas. Catena Aurea on Lk 19:1-10)

So when Jesus was passing through Jericho and stopped at the house of Zacchaeus, he caused a general scandal. The Lord, however, knew exactly what he was doing. He wanted, so to speak, to gamble, and he won the bet: Zacchaeus, deeply moved by Jesus’ visit, decided to change his life, and promised to restore four times what he had stolen. […] God […] sees in everyone a soul to save and is especially attracted to those who are judged as lost and who think themselves so. Jesus Christ, the Incarnation of God, has demonstrated this immense mercy, which takes nothing away from the gravity of sin, but aims always at saving the sinner, at offering him the possibility of redemption, of starting again from the beginning, of converting. (Benedict XVI. Angelus, October 31, 2010)

What then shall we say? Shall we persist in sin that grace may abound? Of course not! How can we who died to sin yet live in it? […] We were indeed buried with him through baptism into death, so that, just as Christ was raised from the dead by the glory of the Father, we too might live in newness of life. […] We know that our old self was crucified with him, so that our sinful body might be done away with, that we might no longer be in slavery to sin. For a dead person has been absolved from sin. […] Therefore, sin must not reign over your mortal bodies so that you obey their desires. And do not present the parts of your bodies to sin as weapons for wickedness, but present yourselves to God as raised from the dead to life and the parts of your bodies to God as weapons for righteousness. (Rom 6:1-13)

This same declaration does Isaias makes: ‘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, it is [here]’ (Jer 7:2-3). (Saint Irenaeus of Lyons. Against Heresies 4, 17, 2-3)

You say you have fellowship with God, and you walk in darkness; ‘and God is light, and in Him is no darkness at all:’ then how should there be fellowship between light and darkness? […] But sins are darkness, as the Apostle says of the devil and his angels, that they are ‘rulers of this darkness’ (Eph 6:12). He would not call them of darkness, save as rulers of sins, having lordship over the wicked. Then what are we to do, my brethren? Fellowship with God must be had, other hope of life eternal is none; […] Let us walk in the light, as He is in the light, that we may be able to have fellowship with Him. (Saint Augustine of Hippo. Homily I on the first letter of Saint John, no. 5)

And lest haply he should seem to have given impunity for sins, in that he said, ‘He is faithful and just to cleanse us from all iniquity;’ and men henceforth should say to themselves, Let us sin, let us do securely what we will, Christ purges us, is faithful and just, purges us from all iniquity: He takes from you an evil security, and puts in an useful fear. To your own hurt you would be secure; you must be solicitous. For ‘He is faithful and just to forgive us our sins,’ provided you always displease yourself, and be changing until you be perfected. […] if from the infirmity of this life sin shall overtake you, see to it straightway, straightway be displeased, straightway condemn it; and when you have condemned, you shall come assured unto the Judge. (Saint Augustine of Hippo. Homily I on the first letter of Saint John, no. 6)

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, and nowhere plainly, nor openly, but in a concealed way. (Saint John Chrysostom. Homilies on Saint Matthew, Homily 80)

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. (Pseudo-Chrysostom, quoted by Saint Thomas Aquinas. Catena Aurea on Mt 21:1-9)

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. Saint 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 Church’s teaching, and in particular her firmness in defending the universal and permanent validity of the precepts prohibiting intrinsically evil acts, is not infrequently seen as the sign of an intolerable intransigence, particularly with regard to the enormously complex and conflict-filled situations present in the moral life of individuals and of society today; this intransigence is said to be in contrast with the Church’s motherhood. The Church, one hears, is lacking in understanding and compassion. But the Church’s motherhood can never in fact be separated from her teaching mission, which she must always carry out as the faithful Bride of Christ, who is the Truth in person. ‘As Teacher, she never tires of proclaiming the moral norm… The Church is in no way the author or the arbiter of this norm. In obedience to the truth which is Christ, whose image is reflected in the nature and dignity of the human person, the Church interprets the moral norm and proposes it to all people of good will, without concealing its demands of radicalness and perfection’. In fact, genuine understanding and compassion must mean love for the person, for his true good, for his authentic freedom. And this does not result, certainly, from concealing or weakening moral truth, but rather from proposing it in its most profound meaning as an outpouring of God’s eternal Wisdom, which we have received in Christ, and as a service to man, to the growth of his freedom and to the attainment of his happiness. (John Paul II. Encyclical Veritatis splendor, no. 95, August 6, 1993)

In effect, to become reconciled with God presupposes and includes detaching oneself consciously and with determination from the sin into which one has fallen. It presupposes and includes, therefore, doing penance in the fullest sense of the term: repenting, showing this repentance, adopting a real attitude of repentance – which is the attitude of the person who starts out on the road of return to the Father. This is a general law and one which each individual must follow in his or her particular situation. For it is not possible to deal with sin and conversion only in abstract terms. In the concrete circumstances of sinful humanity, in which there can be no conversion without the acknowledgment of one’s own sin, the church’s ministry of reconciliation intervenes in each individual case with a precise penitential purpose. That is, the church’s ministry intervenes in order to bring the person to the ‘knowledge of self’ – in the words of Saint Catherine of Siena – to the rejection of evil, to the re-establishment of friendship with God, to a new interior ordering, to a fresh ecclesial conversion. (John Paul II. Apostolic exhortation Reconciliatio et paenitentia, no. 13, December 2, 1984)

Christ’s call to conversion continues to resound in the lives of Christians. This second conversion is an uninterrupted task for the whole Church who, ‘clasping sinners to her bosom, (is) at once holy and always in need of purification, (and) follows constantly the path of penance and renewal.’ This endeavor of conversion is not just a human work. It is the movement of a ‘contrite heart,’ drawn and moved by grace to respond to the merciful love of God who loved us first. (Catechism of the Catholic Church, no. 1428)

In spite of the reality of a loss of the sense of sin, greatly extended in the culture of our times, the priest must practice, with joy and dedication, the ministry of the formation of consciences, pardon and peace. (Congregation for the Clergy. Directory for the ministry and life of priests, no. 51, March 31, 1994)

The sinner who beseeches God the remission of his sins cannot but hear this opportune response: ‘Blessed are the merciful, for they shall obtain mercy’ (Mt 5:7). If then you desire that God have compassion on you, have compassion on your soul. Flood your bed every night with tears; and drench your couch with weeping (Ps 6:7). If you have compassion on yourself, if you produce profound cries of penance, you have already made the first step to the plane of mercy, and with all certainty you shall obtain it. Are you are a great, a very great sinner, and do you ‘in need of an uncommon clemency, of a torrent of mercies’, show yourself also of a great mercy; reconcile with yourself, for you were not well with youself ever since you declared yourself against God. (Saint Bernard of Clairvaux. Of conversion: a sermon to the clergy, Ch. XVI, no. 29)

‘The Lord hath sent me to heal the contrite of heart’ (Is 61:1). God is ready to heal those who sincerely wish to amend their lives, but cannot take pity on the obstinate sinner. The Lord pardons sins, but he cannot pardon those who are determined to offend him. (Saint Alphonsus Liguori. Sermon XV for the First Sunday of Lent, On the number of sins)

‘Whoever blasphemes against the Holy Spirit never has forgiveness, but is guilty of an eternal sin.’ There are no limits to the mercy of God, but anyone who deliberately refuses to accept his mercy by repenting, rejects the forgiveness of his sins and the salvation offered by the Holy Spirit. Such hardness of heart can lead to final impenitence and eternal loss. (Catechism of the Catholic Church, no. 1864)

For the wicked are at war with God, who is offended beyond belief at their crimes; hence the Apostle says: Wrath and indignation, tribulation and anguish upon every soul of man that worketh evil. Although the sinful act is transient, yet the sin by its guilt and stain remains; and the imminent wrath of God pursues it, as the shadow does the body. (Catechism of Trent, 4500)

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? Tell therefore thine offenses in particular, that thou mayest learn for what thou receivest forgiveness, that so thou mayest become grateful towards thy Benefactor. […]when the God of all is provoked, we gape, and throw ourselves back, and live in luxury and in drunkenness, and do all things as usual. And when shall we be able to propitiate Him? and how shall we by this very thing fail to provoke Him so much the more? For not so much sinning, as signing without even pain, causes in Him indignation and wrath. (Saint John Chrysostom. Homilies on Saint Matthew, Homily XIV, no. 5)

‘Is God angry?’ Yes; He is angry with those who act wickedly, but He is good, and kind, and merciful, to those who love and fear Him; for He is a chastener of the godly, and father of the righteous; but he is a judge and punisher of the impious. (Theophilus of Antioch. To Autolycus, Book I, Ch. III)

In this way we ought not to love all equally. […] 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)

Yet all should avoid the society of sinners, as regards fellowship in sin; in this sense it is written (2 Cor. 6:17): ‘Go out from among them…and touch not the unclean thing,’ i.e. by consenting to sin. (Saint Thomas Aquinas. Summa Theologica II-II, q. 25, a. 6, ad. 5)

For, as it is written, ‘They who call you happy cause you to err, and destroy the paths of your feet,’ he who soothes the sinner with flattering blandishments furnishes the stimulus to sin; nor does he repress, but nourishes wrong-doing. But he who, with braver counsels, rebukes at the same time that he instructs a brother, urges him onward to salvation. ‘As many as I love,’ saith the Lord, ‘I rebuke and chasten.’ And thus also it behooves the Lord’s priest not to mislead by deceiving concessions, but to provide with salutary remedies. He is an unskillful physician who handles the swelling edges of wounds with a tender hand, and, by retaining the poison shut up in the deep recesses of the body, increases it. The wound must be opened, and cut, and healed by the stronger remedy of cutting out the corrupting parts. The sick man may cry out, may vociferate, and may complain, in impatience of the pain; but he will afterwards give thanks when he has felt that he is cured. (Saint Cyprian of Carthage. Book on the Lapsed, no 14, ML 4, 477-478)

In answer to them I say in the first place: let no man interpret those passages of Holy Scripture which speak of the present or future existence of good and bad in the Church as meaning that the discipline or vigilance of the Church ought to be relaxed or dispensed with. To give them this meaning would show that a person was ignorant of Scripture and deceived by his own thinking. And in the case of Moses, the servant of god, although he was very patient with those of his people who mingled with foreigners, nevertheless he also punished many even with death. Likewise, Phinees the priest put to death with the sword the adulterers whom he had caught in the act. In these examples we have a sign that the same was to be done in the Church by means of excommunication and degradation, since the external sword was no longer to be used in the discipline of the Church. […] In whatever way these words are understood, whether as meaning that the wicked should be punished by the Church with excommunications, or that each man should remove evil from himself by reproving and correcting himself, nevertheless what was said above is clear, namely, that no man should keep Company with those brethren who are classified with the sinners spoken of above, that is, with notorious and public sinners. (Saint Augustine of Hippo. On Faith and Works, II, 3, pg. 8-9)

But someone may ask, how does Paul bid us, if we have a brother that is a fornicator or covetous man, with such not even to take food; whereas Christ was the guest of publicans? They were not as yet so far advanced as to be brethren, and besides, Saint Paul bids us avoid our brethren only when they persist in evil, but these were converted. (Pseudo-Chrysostom quoted by Saint Thomas Aquinas. Catena Aurea on Lk 19:1-10)

Many shall say to me in that day, Lord, Lord, have we not prophesied in Thy name, and in Thy name have cast out devils, and in Thy name done many wonderful works? And then will I profess unto them, I never knew you: depart from me, ye that work iniquity. There is need of righteousness, that one may deserve well of God the Judge; we must obey His precepts and warnings, that our merits may receive their reward. (Saint Cyprian of Carthage. The Unity of the Church, 15)

The suffering of eternal punishment is in no way opposed to divine justice. Even in the laws men make, punishment need not correspond to the offense in point of time. For the crime of adultery or murder, either of which may be committed in a brief span of time, human law may prescribe lifelong exile or even death, by both of which the criminal is banned forever from the society of the state. Exile, it is true, does not last forever, but this is purely accidental, owing to the fact that man’s life is not everlasting; but the intention of the judge, we may assume, is to sentence the criminal to perpetual punishment, so far as he can. In the same way it is not unjust for God to inflict eternal punishment for a sin committed in a moment of time. We should also take into consideration the fact that eternal punishment is inflicted on a sinner who does not repent of his sin, and so he continues in his sin up to his death. And since he is in sin for eternity, he is reasonably punished by God for all eternity. Furthermore, any sin committed against God has a certain infinity when regarded from the side of God, against whom it is committed. For, clearly, the greater the person who is offended, the more grievous is the offense. He who strikes a soldier is held more gravely accountable than if he struck a peasant; and his offense is much more serious if he strikes a prince or a king. Accordingly, since God is infinitely great, an offense committed against Him is in a certain respect infinite; and so a punishment that is in a certain respect infinite is duly attached to it. Such a punishment cannot be infinite in intensity, for nothing created can be infinite in this way. Consequently a punishment that is infinite in duration is rightly inflicted for mortal sin. Moreover, while a person is still capable of correction, temporal punishment is imposed for his emendation or cleansing. But if a sinner is incorrigible, so that his will is obstinately fixed in sin, as we said above is the case with the damned, his punishment ought never to come to an end. (Saint Thomas Aquinas. Compendium of Theology, Ch. 183)