Whether Penance is a virtue?

Objections

Objection 1 : It would seem that penance is not a virtue. For penance is a sacrament numbered among the other sacraments, as was shown above (Question [84], Article [1]; Question [65], Article [1]). Now no other sacrament is a virtue. Therefore neither is penance a virtue.
Objection 2 : Further, according to the Philosopher (Ethic. iv, 9), "shame is not a virtue," both because it is a passion accompanied by a bodily alteration, and because it is not the disposition of a perfect thing, since it is about an evil act, so that it has no place in a virtuous man. Now, in like manner, penance is a passion accompanied by a bodily alteration, viz. tears, according to Gregory, who says (Hom. xxxiv in Evang.) that "penance consists in deploring past sins": moreover it is about evil deeds, viz. sins, which have no place in a virtuous man. Therefore penance is not a virtue.
Objection 3 : Further, according to the Philosopher (Ethic. iv, 3), "no virtuous man is foolish." But it seems foolish to deplore what has been done in the past, since it cannot be otherwise, and yet this is what we understand by penance. Therefore penance is not a virtue.