HKB
On the contrary, Tully (De Invent. Rhet. ii) reckons it a part of justice.
I answer that, As the Philosopher states (Ethic. ii, 1), aptitude to virtue is in us by nature, but the complement of virtue is in us through habituation or some other cause. Hence it is evident that virtues perfect us so that we follow in due manner our natural inclinations, which belong to the natural right. Wherefore to every definite natural inclination there corresponds a special virtue. Now there is a special inclination of nature to remove harm, for which reason animals have the irascible power distinct from the concupiscible. Man resists harm by defending himself against wrongs, lest they be inflicted on him, or he avenges those which have already been inflicted on him, with the intention, not of harming, but of removing the harm done. And this belongs to vengeance, for Tully says (De Invent. Rhet. ii) that by "vengeance we resist force, or wrong, and in general whatever is obscure" [*Obscurum. Cicero wrote obfuturum but the sense is the same as St. Thomas gives in the parenthesis] "(i.e. derogatory), either by self-defense or by avenging it." Therefore vengeance is a special virtue.
Reply Obj. 1: Just as repayment of a legal debt belongs to commutative justice, and as repayment of a moral debt, arising from the bestowal of a particular favor, belongs to the virtue of gratitude, so too the punishment of sins, so far as it is the concern of public justice, is an act of commutative justice; while so far as it is concerned in defending the rights of the individual by whom a wrong is resisted, it belongs to the virtue of revenge.
Reply Obj. 2: Fortitude disposes to vengeance by removing an obstacle thereto, namely, fear of an imminent danger. Zeal, as denoting the fervor of love, signifies the primary root of vengeance, in so far as a man avenges the wrong done to God and his neighbor, because charity makes him regard them as his own. Now every act of virtue proceeds from charity as its root, since, according to Gregory (Hom. xxvii in Ev.), "there are no green leaves on the bough of good works, unless charity be the root."
Reply Obj. 3: Two vices are opposed to vengeance: one by way of excess, namely, the sin of cruelty or brutality, which exceeds the measure in punishing: while the other is a vice by way of deficiency and consists in being remiss in punishing, wherefore it is written (Prov. 13:24): "He that spareth the rod hateth his son." But the virtue of vengeance consists in observing the due measure of vengeance with regard to all the circumstances.
THIRD ARTICLE [II-II, Q. 108, Art. 3]
Whether Vengeance Should Be Wrought by Means of Punishments Customary Among Men?
Objection 1: It seems that vengeance should not be wrought by means of punishments customary among men. For to put a man to death is to uproot him. But our Lord forbade (Matt. 13:29) the uprooting of the cockle, whereby the children of the wicked one are signified. Therefore sinners should not be put to death.
Obj. 2: Further, all who sin mortally seem to be deserving of the same punishment. Therefore if some who sin mortally are punished with death, it seems that all such persons should be punished with death: and this is evidently false.
Obj. 3: Further, to punish a man publicly for his sin seems to publish his sin: and this would seem to have a harmful effect on the multitude, since the example of sin is taken by them as an occasion for sin. Therefore it seems that the punishment of death should not be inflicted for a sin.
On the contrary, These punishments are fixed by the divine law as appears from what we have said above (I-II, Q. 105, A. 2).