y "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