Summa Th. II-II EN Qu.111 a.4

Whether hypocrisy is always a mortal sin?

Objection: 1. It seems that hypocrisy is always a mortal sin. For Jerome says on Is 16,14: "Of the two evils it is less to sin openly than to simulate holiness": and a gloss on Jb 1,21 [*St. Augustine on Ps 63,7], "As it hath pleased the Lord," etc., says that "pretended justice is no justice, but a twofold sin": and again a gloss on Lam. 4:6, "The iniquity . . . of my people is made greater than the sin of Sodom," says: "He deplores the sins of the soul that falls into hypocrisy, which is a greater iniquity than the sin of Sodom." Now the sins of Sodom are mortal sin. Therefore hypocrisy is always a mortal sin.
2. Further, Gregory says (Moral. xxxi, 8) that hypocrites sin out of malice. But this is most grievous, for it pertains to the sin against the Holy Ghost. Therefore a hypocrite always sins mortally.
3. Further, no one deserves the anger of God and exclusion from seeing God, save on account of mortal sin. Now the anger of God is deserved through hypocrisy according to Jb 36,13, "Dissemblers and crafty men prove the wrath of God": and the hypocrite is excluded from seeing God, according to Jb 13,16, "No hypocrite shall come before His presence." Therefore hypocrisy is always a mortal sin.

On the contrary Hypocrisy is lying by deed since it is a kind of dissimulation. But it is not always a mortal sin to lie by deed. Neither therefore is all hypocrisy a mortal sin.Further, the intention of a hypocrite is to appear to be good. But this is not contrary to charity. Therefore hypocrisy is not of itself a mortal sin.Further, hypocrisy is born of vainglory, as Gregory says (Moral. xxxi, 17). But vainglory is not always a mortal sin. Neither therefore is hypocrisy.
I answer that There are two things in hypocrisy, lack of holiness, and simulation thereof. Accordingly if by a hypocrite we mean a person whose intention is directed to both the above, one, namely, who cares not to be holy but only to appear so, in which sense Sacred Scripture is wont to use the term, it is evident that hypocrisy is a mortal sin: for no one is entirely deprived of holiness save through mortal sin. But if by a hypocrite we mean one who intends to simulate holiness, which he lacks through mortal sin, then, although he is in mortal sin, whereby he is deprived of holiness, yet, in his case, the dissimulation itself is not always a mortal sin, but sometimes a venial sin. This will depend on the end in view; for if this be contrary to the love of God or of his neighbor, it will be a mortal sin: for instance if he were to simulate holiness in order to disseminate false doctrine, or that he may obtain ecclesiastical preferment, though unworthy, or that he may obtain any temporal good in which he fixes his end. If, however, the end intended be not contrary to charity, it will be a venial sin, as for instance when a man takes pleasure in the pretense itself: of such a man it is said in Ethic. iv, 7 that "he would seem to be vain rather than evil"; for the same applies to simulation as to a lie.It happens also sometimes that a man simulates the perfection of holiness which is not necessary for spiritual welfare. Simulation of this kind is neither a mortal sin always, nor is it always associated with mortal sin.

Reply to Objection: 1. This suffices for the Replies to the Objections.


We must now consider boasting and irony, which are parts of lying according to the Philosopher (Ethic. iv, 7). Under the first head, namely, boasting, there are two points of inquiry:

(1) To which virtue is it opposed?

(2) Whether it is a mortal sin?

Whether boasting is opposed to the virtue of truth?

Objection: 1. It seems that boasting is not opposed to the virtue of truth. For lying is opposed to truth. But it is possible to boast even without lying, as when a man makes a show of his own excellence. Thus it is written (Esther 1:3,4) that Assuerus "made a great feast . . . that he might show the riches of the glory" and "of his kingdom, and the greatness and boasting of his power." Therefore boasting is not opposed to the virtue of truth.
2. Further, boasting is reckoned by Gregory (Moral. xxiii, 4) to be one of the four species of pride, "when," to wit, "a man boasts of having what he has not." Hence it is written (Jr 48,29-30): "We have heard the pride of Moab, he is exceeding proud: his haughtiness, and his arrogancy, and his pride, and the loftiness of his heart. I know, saith the Lord, his boasting, and that the strength thereof is not according to it." Moreover, Gregory says (Moral. xxxi, 7) that boasting arises from vainglory. Now pride and vainglory are opposed to the virtue of humility. Therefore boasting is opposed, not to truth, but to humility.
3. Further, boasting seems to be occasioned by riches; wherefore it is written (Sg 5,8): "What hath pride profited us? or what advantage hath the boasting of riches brought us?" Now excess of riches seems to belong to the sin of covetousness, which is opposed to justice or liberality. Therefore boasting is not opposed to truth.

On the contrary The Philosopher says (Ethic. ii, 7; iv, 7), that boasting is opposed to truth.
I answer that "Jactantia" [boasting] seems properly to denote the uplifting of self by words: since if a man wishes to throw [jactare] a thing far away, he lifts it up high. And to uplift oneself, properly speaking, is to talk of oneself above oneself [*Or 'tall-talking' as we should say in English]. This happens in two ways. For sometimes a man speaks of himself, not above what he is in himself, but above that which he is esteemed by men to be: and this the Apostle declines to do when he says (2Co 12,6): "I forbear lest any man should think of me above that which he seeth in me, or anything he heareth of me." In another way a man uplifts himself in words, by speaking of himself above that which he is in reality. And since we should judge of things as they are in themselves, rather than as others deem them to be, it follows that boasting denotes more properly the uplifting of self above what one is in oneself, than the uplifting of self above what others think of one: although in either case it may be called boasting. Hence boasting properly so called is opposed to truth by way of excess.

Reply to Objection: 1. This argument takes boasting as exceeding men's opinion.
2. The sin of boasting may be considered in two ways. First, with regard to the species of the act, and thus it is opposed to truth; as stated (in the body of the article and Question [110], Article [2]). Secondly, with regard to its cause, from which more frequently though not always it arises: and thus it proceeds from pride as its inwardly moving and impelling cause. For when a man is uplifted inwardly by arrogance, it often results that outwardly he boasts of great things about himself; though sometimes a man takes to boasting, not from arrogance, but from some kind of vanity, and delights therein, because he is a boaster by habit. Hence arrogance, which is an uplifting of self above oneself, is a kind of pride; yet it is not the same as boasting, but is very often its cause. For this reason Gregory reckons boasting among the species of pride. Moreover, the boaster frequently aims at obtaining glory through his boasting, and so, according to Gregory, it arises from vainglory considered as its end.
3. Wealth also causes boasting, in two ways. First, as an occasional cause, inasmuch as a man prides himself on his riches. Hence (Pr 8,18) "riches" are significantly described as "proud" [Douay: 'glorious']. Secondly, as being the end of boasting, since according to Ethic. iv, 7, some boast, not only for the sake of glory, but also for the sake of gain. Such people invent stories about themselves, so as to make profit thereby; for instance, they pretend to be skilled in medicine, wisdom, or divination.

Whether boasting is a mortal sin?

Objection: 1. It seems that boasting is a mortal sin. For it is written (Pr 28,25): "He that boasteth, and puffeth himself, stirreth up quarrels." Now it is a mortal sin to stir up quarrels, since God hates those that sow discord, according to Pr 6,19. Therefore boasting is a mortal sin.
2. Further, whatever is forbidden in God's law is a mortal sin. Now a gloss on Si 6,2, "Extol not thyself in the thoughts of thy soul," says: "This is a prohibition of boasting and pride." Therefore boasting is a mortal sin.
3. Further, boasting is a kind of lie. But it is neither an officious nor a jocose lie. This is evident from the end of lying; for according to the Philosopher (Ethic. iv, 7), "the boaster pretends to something greater than he is, sometimes for no further purpose, sometimes for the sake of glory or honor, sometimes for the sake of money." Thus it is evident that it is neither an officious nor a jocose lie, and consequently it must be a mischievous lie. Therefore seemingly it is always a mortal sin.

On the contrary Boasting arises from vainglory, according to Gregory (Moral. xxxi, 17). Now vainglory is not always a mortal sin, but is sometimes a venial sin which only the very perfect avoid. For Gregory says (Moral. viii, 30) that "it belongs to the very perfect, by outward deeds so to seek the glory of their author, that they are not inwardly uplifted by the praise awarded them." Therefore boasting is not always a mortal sin.
I answer that As stated above (Question [110], Article [4]), a mortal sin is one that is contrary to charity. Accordingly boasting may be considered in two ways. First, in itself, as a lie, and thus it is sometimes a mortal, and sometimes a venial sin. It will be a mortal sin when a man boasts of that which is contrary to God's glory---thus it is said in the person of the king of Tyre (Ez 28,2): "Thy heart is lifted up, and thou hast said: I am God"---or contrary to the love of our neighbor, as when a man while boasting of himself breaks out into invectives against others, as told of the Pharisee who said (Lc 18,11): "I am not as the rest of men, extortioners, unjust, adulterers, as also is this publican." Sometimes it is a venial sin, when, to wit, a man boasts of things that are against neither God nor his neighbor. Secondly, it may be considered with regard to its cause, namely, pride, or the desire of gain or of vainglory: and then if it proceeds from pride or from such vainglory as is a mortal sin, then the boasting will also be a mortal sin: otherwise it will be a venial sin. Sometimes, however, a man breaks out into boasting through desire of gain, and for this very reason he would seem to be aiming at the deception and injury of his neighbor: wherefore boasting of this kind is more likely to be a mortal sin. Hence the Philosopher says (Ethic. iv, 7) that "a man who boasts for the sake of gain, is viler than one who boasts for the sake of glory or honor." Yet it is not always a mortal sin because the gain may be such as not to injure another man.

Reply to Objection: 1. To boast in order to stir quarrels is a mortal sin. But it happens sometimes that boasts are the cause of quarrels, not intentionally but accidentally: and consequently boasting will not be a mortal sin on that account.
2. This gloss speaks of boasting as arising from pride that is a mortal sin.
3. Boasting does not always involve a mischievous lie, but only where it is contrary to the love of God or our neighbor, either in itself or in its cause. That a man boast, through mere pleasure in boasting, is an inane thing to do, as the Philosopher remarks (Ethic. iv, 7): wherefore it amounts to a jocose lie. Unless perchance he were to prefer this to the love of God, so as to contemn God's commandments for the sake of boasting: for then it would be against the charity of God, in Whom alone ought our mind to rest as in its last end.To boast for the sake of glory or gain seen to involve an officious lie: provided it be do without injury to others, for then it would once become a mischievous lie.


[*Irony here must be given the signification of the Greek (eironia), whence it is derived: dissimulation of one's own good points.]

We must now consider irony, under which head there are two points of inquiry:

(1) Whether irony is a sin?

(2) Of its comparison with boasting.

Whether irony is a sin?

Objection: 1. It seems that irony, which consists in belittling oneself, is not a sin. For no sin arises from one's being strengthened by God: and yet this leads one to belittle oneself, according to Pr 30,1-2: "The vision which the man spoke, with whom is God, and who being strengthened by God, abiding with him, said, I am the most foolish of men." Also it is written (Amos 7:14): "Amos answered . . . I am not a prophet." Therefore irony, whereby a man belittles himself in words, is not a sin.
2. Further, Gregory says in a letter to Augustine, bishop of the English (Regist. xii): "It is the mark of a well-disposed mind to acknowledge one's fault when one is not guilty." But all sin is inconsistent with a well-disposed mind. Therefore irony is not a sin.
3. Further, it is not a sin to shun pride. But "some belittle themselves in words, so as to avoid pride," according to the Philosopher (Ethic. iv, 7). Therefore irony is not a sin.

On the contrary Augustine says (De Verb. Apost., Serm. xxix): "If thou liest on account of humility, if thou wert not a sinner before lying, thou hast become one by lying."
I answer that To speak so as to belittle oneself may occur in two ways. First so as to safeguard truth, as when a man conceals the greater things in himself, but discovers and asserts lesser things of himself the presence of which in himself he perceives. To belittle oneself in this way does not belong to irony, nor is it a sin in respect of its genus, except through corruption of one of its circumstances. Secondly, a person belittles himself by forsaking the truth, for instance by ascribing to himself something mean the existence of which in himself he does not perceive, or by denying something great of himself, which nevertheless he perceives himself to possess: this pertains to irony, and is always a sin.

Reply to Objection: 1. There is a twofold wisdom and a twofold folly. For there is a wisdom according to God, which has human or worldly folly annexed to it, according to 1Co 3,18, "If any man among you seem to be wise in this world, let him become a fool that he may be wise." But there is another wisdom that is worldly, which as the same text goes on to say, "is foolishness with God." Accordingly, he that is strengthened by God acknowledges himself to be most foolish in the estimation of men, because, to wit, he despises human things, which human wisdom seeks. Hence the text quoted continues, "and the wisdom of men is not with me," and farther on, "and I have known the science of the saints" [*Vulg.: 'and I have not known the science of the saints'].It may also be replied that "the wisdom of men" is that which is acquired by human reason, while the "wisdom of the saints" is that which is received by divine inspiration.Amos denied that he was a prophet by birth, since, to wit, he was not of the race of prophets: hence the text goes on, "nor am I the son of a prophet."
2. It belongs to a well-disposed mind that a man tend to perfect righteousness, and consequently deem himself guilty, not only if he fall short of common righteousness, which is truly a sin, but also if he fall short of perfect righteousness, which sometimes is not a sin. But he does not call sinful that which he does not acknowledge to be sinful: which would be a lie of irony.
3. A man should not commit one sin in order to avoid another: and so he ought not to lie in any way at all in order to avoid pride. Hence Augustine says (Tract. xliii in Joan.): "Shun not arrogance so as to forsake truth": and Gregory says (Moral. xxvi, 3) that "it is a reckless humility that entangles itself with lies."

Whether irony is a less grievous sin than boasting?

Objection: 1. It seems that irony is not a less grievous sin than boasting. For each of them is a sin through forsaking truth, which is a kind of equality. But one does not forsake truth by exceeding it any more than by diminishing it. Therefore irony is not a less grievous sin than boasting.
2. Further, according to the Philosopher (Ethic. iv, 7), irony sometimes is boasting. But boasting is not irony. Therefore irony is not a less grievous sin than boasting.
3. Further, it is written (Pr 26,25): "When he shall speak low, trust him not: because there are seven mischiefs in his heart." Now it belongs to irony to speak low. Therefore it contains a manifold wickedness.

On the contrary The Philosopher says (Ethic. iv, 7): "Those who speak with irony and belittle themselves are more gracious, seemingly, in their manners."
I answer that As stated above (Question [110], Articles [2],4), one lie is more grievous than another, sometimes on account of the matter which it is about---thus a lie about a matter of religious doctrine is most grievous---and sometimes on account of the motive for sinning; thus a mischievous lie is more grievous than an officious or jocose lie. Now irony and boasting lie about the same matter, either by words, or by any other outward signs, namely, about matters affecting the person: so that in this respect they are equal.But for the most part boasting proceeds from a viler motive, namely, the desire of gain or honor: whereas irony arises from a man's averseness, albeit inordinate, to be disagreeable to others by uplifting himself: and in this respect the Philosopher says (Ethic. iv, 7) that "boasting is a more grievous sin than irony."Sometimes, however, it happens that a man belittles himself for some other motive, for instance that he may deceive cunningly: and then irony is more grievous.

Reply to Objection: 1. This argument applies to irony and boasting, according as a lie is considered to be grievous in itself or on account of its matter: for it has been said that in this way they are equal.
2. Excellence is twofold: one is in temporal, the other in spiritual things. Now it happens at times that a person, by outward words or signs, pretends to be lacking in external things, for instance by wearing shabby clothes, or by doing something of the kind, and that he intends by so doing to make a show of some spiritual excellence. Thus our Lord said of certain men (Mt 6,16) that "they disfigure their faces that they may appear unto men to fast." Wherefore such persons are guilty of both vices, irony and boasting, although in different respects, and for this reason they sin more grievously. Hence the Philosopher says (Ethic. iv, 7) that it is "the practice of boasters both to make overmuch of themselves, and to make very little of themselves": and for the same reason it is related of Augustine that he was unwilling to possess clothes that were either too costly or too shabby, because by both do men seek glory.
3. According to the words of Si 19,23, "There is one that humbleth himself wickedly, and his interior is full of deceit," and it is in this sense that Solomon speaks of the man who, through deceitful humility, "speaks low" wickedly.


We must now consider the friendliness which is called affability, and the opposite vices which are flattery and quarreling. Concerning friendliness or affability, there are two points of inquiry:

(1) Whether it is a special virtue?

(2) Whether it is a part of justice?

Whether friendliness is a special virtue?

Objection: 1. It seems that friendliness is not a special virtue. For the Philosopher says (Ethic. viii, 3) that "the perfect friendship is that which is on account of virtue." Now any virtue is the cause of friendship: "since the good is lovable to all," as Dionysius states (Div. Nom. iv). Therefore friendliness is not a special virtue, but a consequence of every virtue.
2. Further, the Philosopher says (Ethic. iv, 6) of this kind of friend that he "takes everything in a right manner both from those he loves and from those who are not his friends." Now it seems to pertain to simulation that a person should show signs of friendship to those whom he loves not, and this is incompatible with virtue. Therefore this kind of friendliness is not a virtue.
3. Further, virtue "observes the mean according as a wise man decides" (Ethic. ii, 6). Now it is written (Qo 7,5): "The heart of the wise is where there is mourning, and the heart of fools where there is mirth": wherefore "it belongs to a virtuous man to be most wary of pleasure" (Ethic. ii, 9). Now this kind of friendship, according to the Philosopher (Ethic. iv, 6), "is essentially desirous of sharing pleasures, but fears to give pain." Therefore this kind of friendliness is not a virtue.

On the contrary The precepts of the law are about acts of virtue. Now it is written (Si 4,7): "Make thyself affable to the congregation of the poor." Therefore affability, which is what we mean by friendship, is a special virtue.
I answer that As stated above (Question [109], Article [2]; FS, Question [55], Article [3]), since virtue is directed to good, wherever there is a special kind of good, there must needs be a special kind of virtue. Now good consists in order, as stated above (Question [109], Article [2]). And it behooves man to be maintained in a becoming order towards other men as regards their mutual relations with one another, in point of both deeds and words, so that they behave towards one another in a becoming manner. Hence the need of a special virtue that maintains the becomingness of this order: and this virtue is called friendliness.

Reply to Objection: 1. The Philosopher speaks of a twofold friendship in his Ethics. One consists chiefly in the affection whereby one man loves another and may result from any virtue. We have stated above, in treating of charity (Question [23], Article [1], Article [3], ad 1; Questions [25],26), what things belong to this kind of friendship. But he mentions another friendliness, which consists merely in outward words or deeds; this has not the perfect nature of friendship, but bears a certain likeness thereto, in so far as a man behaves in a becoming manner towards those with whom he is in contact.
2. Every man is naturally every man's friend by a certain general love; even so it is written (Si 13,19) that "every beast loveth its like." This love is signified by signs of friendship, which we show outwardly by words or deeds, even to those who are strangers or unknown to us. Hence there is no dissimulation in this: because we do not show them signs of perfect friendship, for we do not treat strangers with the same intimacy as those who are united to us by special friendship.
3. When it is said that "the heart of the wise is where there is mourning" it is not that he may bring sorrow to his neighbor, for the Apostle says (Rm 14,15): "If, because of thy meat, thy brother be grieved, thou walkest not now according to charity": but that he may bring consolation to the sorrowful, according to Si 7,38, "Be not wanting in comforting them that weep, and walk with them that mourn." Again, "the heart of fools is where there is mirth," not that they may gladden others, but that they may enjoy others' gladness. Accordingly, it belongs to the wise man to share his pleasures with those among whom he dwells, not lustful pleasures, which virtue shuns, but honest pleasures, according to Ps 132,1, "Behold how good and how pleasant it is for brethren to dwell together in unity."Nevertheless, as the Philosopher says (Ethic. iv, 6), for the sake of some good that will result, or in order to avoid some evil, the virtuous man will sometimes not shrink from bringing sorrow to those among whom he lives. Hence the Apostle says (2Co 7,8): "Although I made you sorrowful by my epistle, I do not repent," and further on (2Co 7,9), "I am glad; not because you were made sorrowful, but because you were made sorrowful unto repentance." For this reason we should not show a cheerful face to those who are given to sin, in order that we may please them, lest we seem to consent to their sin, and in a way encourage them to sin further. Hence it is written (Si 7,26): "Hast thou daughters? Have a care of their body, and show not thy countenance gay towards them."

Whether this kind of friendship is a part of justice?

Objection: 1. It seems that this kind of friendship is not a part of justice. For justice consists in giving another man his due. But this virtue does not consist in doing that, but in behaving agreeably towards those among whom we live. Therefore this virtue is not a part of justice.
2. Further, according to the Philosopher (Ethic. iv, 6), this virtue is concerned about the joys and sorrows of those who dwell in fellowship. Now it belongs to temperance to moderate the greatest pleasures, as stated above (FS, Question [60], Article [5]; FS, Question [61], Article [3]). Therefore this virtue is a part of temperance rather than of justice.
3. Further, to give equal things to those who are unequal is contrary to justice, as stated above (Question [59], Articles [1],2). Now, according to the Philosopher (Ethic. iv, 6), this virtue "treats in like manner known and unknown, companions and strangers." Therefore this virtue rather than being a part of justice is opposed thereto.

On the contrary Macrobius (De Somno Scip. i) accounts friendship a part of justice.
I answer that This virtue is a part of justice, being annexed to it as to a principal virtue. Because in common with justice it is directed to another person, even as justice is: yet it falls short of the notion of justice, because it lacks the full aspect of debt, whereby one man is bound to another, either by legal debt, which the law binds him to pay, or by some debt arising out of a favor received. For it regards merely a certain debt of equity, namely, that we behave pleasantly to those among whom we dwell, unless at times, for some reason, it be necessary to displease them for some good purpose.

Reply to Objection: 1. As we have said above (Question [109], Article [3], ad 1), because man is a social animal he owes his fellow-man, in equity, the manifestation of truth without which human society could not last. Now as man could not live in society without truth, so likewise, not without joy, because, as the Philosopher says (Ethic. viii), no one could abide a day with the sad nor with the joyless. Therefore, a certain natural equity obliges a man to live agreeably with his fellow-men; unless some reason should oblige him to sadden them for their good.
2. It belongs to temperance to curb pleasures of the senses. But this virtue regards the pleasures of fellowship, which have their origin in the reason, in so far as one man behaves becomingly towards another. Such pleasures need not to be curbed as though they were noisome.
3. This saying of the Philosopher does not mean that one ought to converse and behave in the same way with acquaintances and strangers, since, as he says (Ethic. iv, 6), "it is not fitting to please and displease intimate friends and strangers in the same way." This likeness consists in this, that we ought to behave towards all in a fitting manner.



We must now consider the vices opposed to the aforesaid virtue: (1) Flattery, and (2) Quarreling. Concerning flattery there are two points of inquiry:

(1) Whether flattery is a sin?

(2) Whether it is a mortal sin?

Whether flattery is a sin?

Objection: 1. It seems that flattery is not a sin. For flattery consists in words of praise offered to another in order to please him. But it is not a sin to praise a person, according to Pr 31,28, "Her children rose up and called her blessed: her husband, and he praised her." Moreover, there is no evil in wishing to please others, according to 1Co 10,33, "I . . . in all things please all men." Therefore flattery is not a sin.
2. Further, evil is contrary to good, and blame to praise. But it is not a sin to blame evil. Neither, then, is it a sin to praise good, which seems to belong to flattery. Therefore flattery is not a sin.
3. Further, detraction is contrary to flattery. Wherefore Gregory says (Moral. xxii, 5) that detraction is a remedy against flattery. "It must be observed," says he, "that by the wonderful moderation of our Ruler, we are often allowed to be rent by detractions but are uplifted by immoderate praise, so that whom the voice of the flatterer upraises, the tongue of the detractor may humble." But detraction is an evil, as stated above (Question [73], Articles [2],3). Therefore flattery is a good.

On the contrary A gloss on Ez 13,18, "Woe to them that sew cushions under every elbow," says, "that is to say, sweet flattery." Therefore flattery is a sin.
I answer that As stated above (Question [114], Article [1], ad 3), although the friendship of which we have been speaking, or affability, intends chiefly the pleasure of those among whom one lives, yet it does not fear to displease when it is a question of obtaining a certain good, or of avoiding a certain evil. Accordingly, if a man were to wish always to speak pleasantly to others, he would exceed the mode of pleasing, and would therefore sin by excess. If he do this with the mere intention of pleasing he is said to be "complaisant," according to the Philosopher (Ethic. iv, 6): whereas if he do it with the intention of making some gain out of it, he is called a "flatterer" or "adulator." As a rule, however, the term "flattery" is wont to be applied to all who wish to exceed the mode of virtue in pleasing others by words or deeds in their ordinary behavior towards their fellows.

Reply to Objection: 1. One may praise a person both well and ill, according as one observes or omits the due circumstances. For if while observing other due circumstances one were to wish to please a person by praising him, in order thereby to console him, or that he may strive to make progress in good, this will belong to the aforesaid virtue of friendship. But it would belong to flattery, if one wished to praise a person for things in which he ought not to be praised; since perhaps they are evil, according to Ps 9,24, "The sinner is praised in the desires of his soul"; or they may be uncertain, according to Si 27,8, "Praise not a man before he speaketh," and again (Si 11,2), "Praise not a man for his beauty"; or because there may be fear lest human praise should incite him to vainglory, wherefore it is written, (Si 11,30), "Praise not any man before death." Again, in like manner it is right to wish to please a man in order to foster charity, so that he may make spiritual progress therein. But it would be sinful to wish to please men for the sake of vainglory or gain, or to please them in something evil, according to Ps 52,6, "God hath scattered the bones of them that please men," and according to the words of the Apostle (Ga 1,10), "If I yet pleased men, I should not be the servant of Christ."
2. Even to blame evil is sinful, if due circumstances be not observed; and so too is it to praise good.
3. Nothing hinders two vices being contrary to one another. Wherefore even as detraction is evil, so is flattery, which is contrary thereto as regards what is said, but not directly as regards the end. Because flattery seeks to please the person flattered, whereas the detractor seeks not the displeasure of the person defamed, since at times he defames him in secret, but seeks rather his defamation.

Whether flattery is a mortal sin?

Objection: 1. It seems that flattery is a mortal sin. For, according to Augustine (Enchiridion xii), "a thing is evil because it is harmful." But flattery is most harmful, according to Ps 9,24, "For the sinner is praised in the desires of his soul, and the unjust man is blessed. The sinner hath provoked the Lord." Wherefore Jerome says (Ep ad Celant): "Nothing so easily corrupts the human mind as flattery": and a gloss on Ps 69,4, "Let them be presently turned away blushing for shame that say to me: 'Tis well, 'Tis well," says: "The tongue of the flatterer harms more than the sword of the persecutor." Therefore flattery is a most grievous sin.
2. Further, whoever does harm by words, harms himself no less than others: wherefore it is written (Ps 36,15): "Let their sword enter into their own hearts." Now he that flatters another induces him to sin mortally: hence a gloss on Ps 140,5, "Let not the oil of the sinner fatten my head," says: "The false praise of the flatterer softens the mind by depriving it of the rigidity of truth and renders it susceptive of vice." Much more, therefore, does the flatterer sin in himself.
3. Further, it is written in the Decretals (D. XLVI, Cap. 3): "The cleric who shall be found to spend his time in flattery and treachery shall be degraded from his office." Now such a punishment as this is not inflicted save for mortal sin. Therefore flattery is a mortal sin.

On the contrary Augustine in a sermon on Purgatory (xli, de Sanctis) reckons among slight sins, "if one desire to flatter any person of higher standing, whether of one's own choice, or out of necessity."
I answer that As stated above (Question [112], Article [2]), a mortal sin is one that is contrary to charity. Now flattery is sometimes contrary to charity and sometimes not. It is contrary to charity in three ways. First, by reason of the very matter, as when one man praises another's sin: for this is contrary to the love of God, against Whose justice he speaks, and contrary to the love of his neighbor, whom he encourages to sin. Wherefore this is a mortal sin, according to Is 5,20. "Woe to you that call evil good." Secondly, by reason of the intention, as when one man flatters another, so that by deceiving him he may injure him in body or in soul; this is also a mortal sin, and of this it is written (Pr 27,6): "Better are the wounds of a friend than the deceitful kisses of an enemy." Thirdly, by way of occasion, as when the praise of a flatterer, even without his intending it, becomes to another an occasion of sin. In this case it is necessary to consider, whether the occasion were given or taken, and how grievous the consequent downfall, as may be understood from what has been said above concerning scandal (Question [43], Articles [3],4). If, however, one man flatters another from the mere craving to please others, or again in order to avoid some evil, or to acquire something in a case of necessity, this is not contrary to charity. Consequently it is not a mortal but a venial sin.

Reply to Objection: 1. The passages quoted speak of the flatterer who praises another's sin. Flattery of this kind is said to harm more than the sword of the persecutor, since it does harm to goods that are of greater consequence. namely, spiritual goods. Yet it does not harm so efficaciously, since the sword of the persecutor slays effectively, being a sufficient cause of death; whereas no one by flattering can be a sufficient cause of another's sinning, as was shown above (Question [43], Article [1], ad 3; FS, Question [73], Article [8], ad 3; FS, Question [80], Article [1]).
2. This argument applies to one that flatters with the intention of doing harm: for such a man harms himself more than others, since he harms himself, as the sufficient cause of sinning, whereas he is only the occasional cause of the harm he does to others.
3. The passage quoted refers to the man who flatters another treacherously, in order to deceive him.

Summa Th. II-II EN Qu.111 a.4