Whether any virtue is caused in us by habituation?

Objections

Objection 1 : It would seem that virtues can not be caused in us by habituation. Because a gloss of Augustine [*Cf. Lib. Sentent. Prosperi cvi.] commenting on Rm. 14:23, "All that is not of faith is sin," says: "The whole life of an unbeliever is a sin: and there is no good without the Sovereign Good. Where knowledge of the truth is lacking, virtue is a mockery even in the best behaved people." Now faith cannot be acquired by means of works, but is caused in us by God, according to Eph. 2:8: "By grace you are saved through faith." Therefore no acquired virtue can be in us by habituation.
Objection 2 : Further, sin and virtue are contraries, so that they are incompatible. Now man cannot avoid sin except by the grace of God, according to Wis. 8:21: "I knew that I could not otherwise be continent, except God gave it." Therefore neither can any virtues be caused in us by habituation, but only by the gift of God.
Objection 3 : Further, actions which lead toward virtue, lack the perfection of virtue. But an effect cannot be more perfect than its cause. Therefore a virtue cannot be caused by actions that precede it.