If you have justified anger and you have thoughts about killing because of it then does that constitute mortal sin? Does the thought of killing alone constitute mortal sin or is the thought alone not sufficient? Perhaps it would require a commitment after having the thought. At what point does the anger become mortal sin even if the anger is justified?

Summa Theologica[/i], Secunda Secundæ Partis, Question 158]Article 1. Whether it is lawful to be angry?

Objection 1. It would seem that it cannot be lawful to be angry. For Jerome in his exposition on Matthew 5:22, "Whosoever is angry with his brother," etc. says: "Some codices add 'without cause.' However, in the genuine codices the sentence is unqualified, and anger is forbidden altogether." Therefore it is nowise lawful to be angry.

Objection 2. Further, according to Dionysius (Div. Nom. iv) "The soul's evil is to be without reason." Now anger is always without reason: for the Philosopher says (Ethic. vii, 6) that "anger does not listen perfectly to reason"; and Gregory says (Moral. v, 45) that "when anger sunders the tranquil surface of the soul, it mangles and rends it by its riot"; and Cassian says (De Inst. Caenob. viii, 6): "From whatever cause it arises, the angry passion boils over and blinds the eye of the mind." Therefore it is always evil to be angry.

Objection 3. Further, anger is "desire for vengeance" [Aristotle, Rhet. ii, 2 according to a gloss on Leviticus 19:17, "Thou shalt not hate thy brother in thy heart." Now it would seem unlawful to desire vengeance, since this should be left to God, according to Deuteronomy 32:35, "Revenge is Mine." Therefore it would seem that to be angry is always an evil.

Objection 4. Further, all that makes us depart from likeness to God is evil. Now anger always makes us depart from likeness to God, since God judges with tranquillity according to Wisdom 12:18. Therefore to be angry is always an evil.

On the contrary, Chrysostom [Hom. xi in the Opus Imperfectum, falsely ascribed to St. John Chrysostom] says: "He that is angry without cause, shall be in danger; but he that is angry with cause, shall not be in danger: for without anger, teaching will be useless, judgments unstable, crimes unchecked." Therefore to be angry is not always an evil.

I answer that, Properly speaking anger is a passion of the sensitive appetite, and gives its name to the irascible power, as stated above (I-II, 46, 1) when we were treating of the passions. Now with regard to the passions of the soul, it is to be observed that evil may be found in them in two ways. First by reason of the passion's very species, which is derived from the passion's object. Thus envy, in respect of its species, denotes an evil, since it is displeasure at another's good, and such displeasure is in itself contrary to reason: wherefore, as the Philosopher remarks (Ethic. ii, 6), "the very mention of envy denotes something evil." Now this does not apply to anger, which is the desire for revenge, since revenge may be desired both well and ill. Secondly, evil is found in a passion in respect of the passion's quantity, that is in respect of its excess or deficiency; and thus evil may be found in anger, when, to wit, one is angry, more or less than right reason demands. But if one is angry in accordance with right reason, one's anger is deserving of praise.

Reply to Objection 1. The Stoics designated anger and all the other passions as emotions opposed to the order of reason; and accordingly they deemed anger and all other passions to be evil, as stated above (I-II, 24, 2) when we were treating of the passions. It is in this sense that Jerome considers anger; for he speaks of the anger whereby one is angry with one's neighbor, with the intent of doing him a wrong.--But, according to the Peripatetics, to whose opinion Augustine inclines (De Civ. Dei ix, 4), anger and the other passions of the soul are movements of the sensitive appetite, whether they be moderated or not, according to reason: and in this sense anger is not always evil.

Reply to Objection 2. Anger may stand in a twofold relation to reason. First, antecedently; in this way it withdraws reason from its rectitude, and has therefore the character of evil. Secondly, consequently, inasmuch as the movement of the sensitive appetite is directed against vice and in accordance with reason, this anger is good, and is called "zealous anger." Wherefore Gregory says (Moral. v, 45): "We must beware lest, when we use anger as an instrument of virtue, it overrule the mind, and go before it as its mistress, instead of following in reason's train, ever ready, as its handmaid, to obey." This latter anger, although it hinder somewhat the judgment of reason in the execution of the act, does not destroy the rectitude of reason. Hence Gregory says (Moral. v, 45) that "zealous anger troubles the eye of reason, whereas sinful anger blinds it." Nor is it incompatible with virtue that the deliberation of reason be interrupted in the execution of what reason has deliberated: since art also would be hindered in its act, if it were to deliberate about what has to be done, while having to act.

Reply to Objection 3. It is unlawful to desire vengeance considered as evil to the man who is to be punished, but it is praiseworthy to desire vengeance as a corrective of vice and for the good of justice; and to this the sensitive appetite can tend, in so far as it is moved thereto by the reason: and when revenge is taken in accordance with the order of judgment, it is God's work, since he who has power to punish "is God's minister," as stated in Romans 13:4.

Reply to Objection 4. We can and ought to be like to God in the desire for good; but we cannot be altogether likened to Him in the mode of our desire, since in God there is no sensitive appetite, as in us, the movement of which has to obey reason. Wherefore Gregory says (Moral. v, 45) that "anger is more firmly erect in withstanding vice, when it bows to the command of reason."

Article 2. Whether anger is a sin?

Objection 1. It would seem that anger is not a sin. For we demerit by sinning. But "we do not demerit by the passions, even as neither do we incur blame thereby," as stated in Ethic. ii, 5. Consequently no passion is a sin. Now anger is a passion as stated above (I-II, 46, 1) in the treatise on the passions. Therefore anger is not a sin.

Objection 2. Further, in every sin there is conversion to some mutable good. But in anger there is conversion not to a mutable good, but to a person's evil. Therefore anger is not a sin.

Objection 3. Further, "No man sins in what he cannot avoid," as Augustine asserts [De Lib. Arb. iii, 18. But man cannot avoid anger, for a gloss on Psalm 4:5, "Be ye angry and sin not," says: "The movement of anger is not in our power." Again, the Philosopher asserts (Ethic. vii, 6) that "the angry man acts with displeasure." Now displeasure is contrary to the will. Therefore anger is not a sin.

Objection 4. Further, sin is contrary to nature, according to Damascene [De Fide Orth. ii, 4,30. But it is not contrary to man's nature to be angry, and it is the natural act of a power, namely the irascible; wherefore Jerome says in a letter [Ep. xii ad Anton. Monach.] that "to be angry is the property of man." Therefore it is not a sin to be angry.

On the contrary, The Apostle says (Ephesians 4:31): "Let all indignation and anger [Vulgate: 'Anger and indignation'] . . . be put away from you."

I answer that, Anger, as stated above (Article 1), is properly the name of a passion. A passion of the sensitive appetite is good in so far as it is regulated by reason, whereas it is evil if it set the order of reason aside. Now the order of reason, in regard to anger, may be considered in relation to two things. First, in relation to the appetible object to which anger tends, and that is revenge. Wherefore if one desire revenge to be taken in accordance with the order of reason, the desire of anger is praiseworthy, and is called "zealous anger" [Cf. Gregory, Moral. v, 45. On the other hand, if one desire the taking of vengeance in any way whatever contrary to the order of reason, for instance if he desire the punishment of one who has not deserved it, or beyond his deserts, or again contrary to the order prescribed by law, or not for the due end, namely the maintaining of justice and the correction of defaults, then the desire of anger will be sinful, and this is called sinful anger.

Secondly, the order of reason in regard to anger may be considered in relation to the mode of being angry, namely that the movement of anger should not be immoderately fierce, neither internally nor externally; and if this condition be disregarded, anger will not lack sin, even though just vengeance be desired.

Reply to Objection 1. Since passion may be either regulated or not regulated by reason, it follows that a passion considered absolutely does not include the notion of merit or demerit, of praise or blame. But as regulated by reason, it may be something meritorious and deserving of praise; while on the other hand, as not regulated by reason, it may be demeritorious and blameworthy. Wherefore the Philosopher says (Ethic. ii, 5) that "it is he who is angry in a certain way, that is praised or blamed."

Reply to Objection 2. The angry man desires the evil of another, not for its own sake but for the sake of revenge, towards which his appetite turns as to a mutable good.

Reply to Objection 3. Man is master of his actions through the judgment of his reason, wherefore as to the movements that forestall that judgment, it is not in man's power to prevent them as a whole, i.e. so that none of them arise, although his reason is able to check each one, if it arise. Accordingly it is stated that the movement of anger is not in man's power, to the extent namely that no such movement arise. Yet since this movement is somewhat in his power, it is not entirely sinless if it be inordinate. The statement of the Philosopher that "the angry man acts with displeasure," means that he is displeased, not with his being angry, but with the injury which he deems done to himself: and through this displeasure he is moved to seek vengeance.

Reply to Objection 4. The irascible power in man is naturally subject to his reason, wherefore its act is natural to man, in so far as it is in accord with reason, and in so far as it is against reason, it is contrary to man's nature.

Article 3. Whether all anger is a mortal sin?

Objection 1. It would seem that all anger is a mortal sin. For it is written (Job 5:2): "Anger killeth the foolish man [Vulgate: 'Anger indeed killeth the foolish']," and he speaks of the spiritual killing, whence mortal sin takes its name. Therefore all anger is a mortal sin.

Objection 2. Further, nothing save mortal sin is deserving of eternal condemnation. Now anger deserves eternal condemnation; for our Lord said (Matthew 5:22): "Whosoever is angry with his brother shall be in danger of the judgment": and a gloss on this passage says that "the three things mentioned there, namely judgment, council, and hell-fire, signify in a pointed manner different abodes in the state of eternal damnation corresponding to various sins." Therefore anger is a mortal sin.

Objection 3. Further, whatsoever is contrary to charity is a mortal sin. Now anger is of itself contrary to charity, as Jerome declares in his commentary on Matthew 5:22, "Whosoever is angry with his brother," etc. where he says that this is contrary to the love of your neighbor. Therefore anger is a mortal sin.

On the contrary, A gloss on Psalm 4:5, "Be ye angry and sin not," says: "Anger is venial if it does not proceed to action."

I answer that, The movement of anger may be inordinate and sinful in two ways, as stated above (Article 2). First, on the part of the appetible object, as when one desires unjust revenge; and thus anger is a mortal sin in the point of its genus, because it is contrary to charity and justice. Nevertheless such like anger may happen to be a venial sin by reason of the imperfection of the act. This imperfection is considered either in relation to the subject desirous of vengeance, as when the movement of anger forestalls the judgment of his reason; or in relation to the desired object, as when one desires to be avenged in a trifling matter, which should be deemed of no account, so that even if one proceeded to action, it would not be a mortal sin, for instance by pulling a child slightly by the hair, or by some other like action. Secondly, the movement of anger may be inordinate in the mode of being angry, for instance, if one be too fiercely angry inwardly, or if one exceed in the outward signs of anger. On this way anger is not a mortal sin in the point of its genus; yet it may happen to be a mortal sin, for instance if through the fierceness of his anger a man fall away from the love of God and his neighbor.

Reply to Objection 1. It does not follow from the passage quoted that all anger is a mortal sin, but that the foolish are killed spiritually by anger, because, through not checking the movement of anger by their reason, they fall into mortal sins, for instance by blaspheming God or by doing injury to their neighbor.

Reply to Objection 2. Our Lord said this of anger, by way of addition to the words of the Law: "Whosoever shall kill shall be in danger of the judgment" (Matthew 5:21). Consequently our Lord is speaking here of the movement of anger wherein a man desires the killing or any grave injury of his neighbor: and should the consent of reason be given to this desire, without doubt it will be a mortal sin.

Reply to Objection 3. In the case where anger is contrary to charity, it is a mortal sin, but it is not always so, as appears from what we have said.

Article 4. Whether anger is the most grievous sin?

Objection 1. It would seem that anger is the most grievous sin. For Chrysostom says [Hom. xlviii in Joan.] that "nothing is more repulsive than the look of an angry man, and nothing uglier than a ruthless* face, and most of all than a cruel soul." ['Severo'. The correct text is 'Si vero.' The translation would then run thus . . . 'and nothing uglier.' And if his 'face is ugly, how much uglier is his soul!']. Therefore anger is the most grievous sin.

Objection 2. Further, the more hurtful a sin is, the worse it would seem to be; since, according to Augustine (Enchiridion xii), "a thing is said to be evil because it hurts." Now anger is most hurtful, because it deprives man of his reason, whereby he is master of himself; for Chrysostom says (Hom. xlviii in Joan.) that "anger differs in no way from madness; it is a demon while it lasts, indeed more troublesome than one harassed by a demon." Therefore anger is the most grievous sin.

Objection 3. Further, inward movements are judged according to their outward effects. Now the effect of anger is murder, which is a most grievous sin. Therefore anger is a most grievous sin.

On the contrary, Anger is compared to hatred as the mote to the beam; for Augustine says in his Rule (Ep. ccxi): "Lest anger grow into hatred and a mote become a beam." Therefore anger is not the most grievous sin.

I answer that, As stated above (1 and 2), the inordinateness of anger is considered in a twofold respect, namely with regard to an undue object, and with regard to an undue mode of being angry. As to the appetible object which it desires, anger would seem to be the least of sins, for anger desires the evil of punishment for some person, under the aspect of a good that is vengeance. Hence on the part of the evil which it desires the sin of anger agrees with those sins which desire the evil of our neighbor, such as envy and hatred; but while hatred desires absolutely another's evil as such, and the envious man desires another's evil through desire of his own glory, the angry man desires another's evil under the aspect of just revenge. Wherefore it is evident that hatred is more grievous than envy, and envy than anger: since it is worse to desire evil as an evil, than as a good; and to desire evil as an external good such as honor or glory, than under the aspect of the rectitude of justice. On the part of the good, under the aspect of which the angry man desires an evil, anger concurs with the sin of concupiscence that tends to a good. On this respect again, absolutely speaking. the sin of anger is apparently less grievous than that of concupiscence, according as the good of justice, which the angry man desires, is better than the pleasurable or useful good which is desired by the subject of concupiscence. Wherefore the Philosopher says (Ethic. vii, 4) that "the incontinent in desire is more disgraceful than the incontinent in anger."

On the other hand, as to the inordinateness which regards the mode of being angry, anger would seem to have a certain pre-eminence on account of the strength and quickness of its movement, according to Proverbs 27:4, "Anger hath no mercy, nor fury when it breaketh forth: and who can bear the violence of one provoked?" Hence Gregory says (Moral. v, 45): "The heart goaded by the pricks of anger is convulsed, the body trembles, the tongue entangles itself, the face is inflamed, the eyes are enraged and fail utterly to recognize those whom we know: the tongue makes sounds indeed, but there is no sense in its utterance."

Reply to Objection 1. Chrysostom is alluding to the repulsiveness of the outward gestures which result from the impetuousness of anger.

Reply to Objection 2. This argument considers the inordinate movement of anger, that results from its impetuousness, as stated above.

Reply to Objection 3. Murder results from hatred and envy no less than from anger: yet anger is less grievous, inasmuch as it considers the aspect of justice, as stated above.