Reply Obj. 1: Meekness regards properly the desire itself of vengeance; whereas clemency regards the punishment itself which is applied externally for the purpose of vengeance.
Reply Obj. 2: Man's affections incline to the moderation of things that are unpleasant to him in themselves. Now it results from one man loving another that he takes no pleasure in the latter's punishment in itself, but only as directed to something else, for instance justice, or the correction of the person punished. Hence love makes one quick to mitigate punishment—and this pertains to clemency—while hatred is an obstacle to such mitigation. For this reason Tully says that "the mind provoked to hatred" that is to punish too severely, "is restrained by clemency," from inflicting too severe a punishment, so that clemency directly moderates not hatred but punishment.
Reply Obj. 3: The vice of anger, which denotes excess in the passion of anger, is properly opposed to meekness, which is directly concerned with the passion of anger; while cruelty denotes excess in punishing. Wherefore Seneca says (De Clementia ii, 4) that "those are called cruel who have reason for punishing, but lack moderation in punishing." Those who delight in a man's punishment for its own sake may be called savage or brutal, as though lacking the human feeling that leads one man to love another. _______________________
SECOND ARTICLE [II-II, Q. 157, Art. 2]
Whether Both Clemency and Meekness Are Virtues?
Objection 1: It would seem that neither clemency nor meekness is a virtue. For no virtue is opposed to another virtue. Yet both of these are apparently opposed to severity, which is a virtue. Therefore neither clemency nor meekness is a virtue.
Obj. 2: Further, "Virtue is destroyed by excess and defect" [*Ethic. ii, 2]. But both clemency and meekness consist in a certain decrease; for clemency decreases punishment, and meekness decreases anger. Therefore neither clemency nor meekness is a virtue.
Obj. 3: Further, meekness or mildness is included (Matt. 5:4) among the beatitudes, and (Gal. 5:23) among the fruits. Now the virtues differ from the beatitudes and fruits. Therefore they are not comprised under virtue.
On the contrary, Seneca says (De Clementia ii, 5): "Every good man is conspicuous for his clemency and meekness." Now it is virtue properly that belongs to a good man, since "virtue it is that makes its possessor good, and renders his works good also" (Ethic. ii, 6). Therefore clemency and meekness are virtues.
I answer that, The nature of moral virtue consists in the subjection of appetite to reason, as the Philosopher declares (Ethic. i, 13). Now this is verified both in clemency and in meekness. For clemency, in mitigating punishment, "is guided by reason," according to Seneca (De Clementia ii, 5), and meekness, likewise, moderates anger according to right reason, as stated in Ethic. iv, 5. Wherefore it is manifest that both clemency and meekness are virtues.