Objection 1. It would seem that virginity is not a virtue. For "no virtue is in us by nature," as the Philosopher says (Ethic. ii, 1). Now virginity is in us by nature, since all are virgins when born. Therefore virginity is not a virtue.
Objection 2. Further, whoever has one virtue has all virtues, as stated above (I-II, 65, 1). Yet some have other virtues without having virginity: else, since none can go to the heavenly kingdom without virtue, no one could go there without virginity, which would involve the condemnation of marriage. Therefore virginity is not a virtue.
Objection 3. Further, every virtue is recovered by penance. But virginity is not recovered by penance: wherefore Jerome says [Ep. xxii ad Eustoch.]: "Other things God can do, but He cannot restore the virgin after her downfall." Therefore seemingly virginity is not a virtue.
Objection 4. Further, no virtue is lost without sin. Yet virginity is lost without sin, namely by marriage. Therefore virginity is not a virtue.
Objection 5. Further, virginity is condivided with widowhood and conjugal purity. But neither of these is a virtue. Therefore virginity is not a virtue.
On the contrary, Ambrose says (De Virgin. i, 3): "Love of virginity moves us to say something about virginity, lest by passing it over we should seem to cast a slight on what is a virtue of high degree."
I answer that, As stated above (Article 1), the formal and completive element in virginity is the purpose of abstaining from venereal pleasure, which purpose is rendered praiseworthy by its end, in so far, to wit, as this is done in order to have leisure for Divine things: while the material element in virginity is integrity of the flesh free of all experience of venereal pleasure. Now it is manifest that where a good action has a special matter through having a special excellence, there is a special kind of virtue: for example, magnificence which is about great expenditure is for this reason a special virtue distinct from liberality, which is about all uses of money in general. Now to keep oneself free from the experience of venereal pleasure has an excellence of its own deserving of greater praise than keeping oneself free from inordinate venereal pleasure. Wherefore virginity is a special virtue being related to chastity as magnificence to liberality.
Reply to Objection 1. Men have from their birth that which is material in virginity, namely integrity of the flesh and freedom from venereal experience. But they have not that which is formal in virginity, namely the purpose of safeguarding this integrity for God's sake, which purpose gives virginity its character of virtue. Hence Augustine says (De Virgin. xi): "Nor do we praise virgins for being virgins, but, because their virginity is consecrated to God by holy continency."
Reply to Objection 2. Virtues are connected together by reason of that which is formal in them, namely charity, or by reason of prudence, as stated above (129, 3, ad 2), but not by reason of that which is material in them. For nothing hinders a virtuous man from providing the matter of one virtue, and not the matter of another virtue: thus a poor man has the matter of temperance, but not that of magnificence. It is in this way that one who has the other virtues lacks the matter of virginity, namely the aforesaid integrity of the flesh: nevertheless he can have that which is formal in virginity, his mind being so prepared that he has the purpose of safeguarding this same integrity of the flesh, should it be fitting for him to do so: even as a poor man may be so prepared in mind as to have the purpose of being magnificent in his expenditure, were he in a position to do so: or again as a prosperous man is so prepared in mind as to purpose bearing misfortune with equanimity: without which preparedness of the mind no man can be virtuous.
Reply to Objection 3. Virtue can be recovered by penance as regards that which is formal in virtue, but not as to that which is material therein. For if a magnificent man has squandered all his wealth he does not recover his riches by repenting of his sin. On like manner a person who has lost virginity by sin, recovers by repenting, not the matter of virginity but the purpose of virginity.
As regards the matter of virginity there is that which can be miraculously restored by God, namely the integrity of the organ, which we hold to be accidental to virginity: while there is something else which cannot be restored even by miracle, to wit, that one who has experienced venereal lust should cease to have had that experience. For God cannot make that which is done not to have been done, as stated in I, 25, 4.
Reply to Objection 4. Virginity as a virtue denotes the purpose, confirmed by vow, of observing perpetual integrity. For Augustine says (De Virgin. viii) that "by virginity, integrity of the flesh is vowed, consecrated and observed in honor of the Creator of both soul and flesh." Hence virginity, as a virtue, is never lost without sin.
Reply to Objection 5. Conjugal chastity is deserving of praise merely because it abstains from unlawful pleasures: hence no excellence attaches to it above that of chastity in general. Widowhood, however, adds something to chastity in general; but it does not attain to that which is perfect in this matter, namely to entire freedom from venereal pleasure; virginity alone achieves this. Wherefore virginity alone is accounted a virtue above chastity, even as magnificence is reckoned above liberality.
Source: Summa Theologica (New Advent)