Objection 1. It would seem that the moral virtues pertain to the contemplative life. For Gregory says (Hom. xiv in Ezech.) that "the contemplative life is to cling to the love of God and our neighbor with the whole mind." Now all the moral virtues, since their acts are prescribed by the precepts of the Law, are reducible to the love of God and of our neighbor, for "love... is the fulfilling of the Law" (Romans 13:1)0). Therefore it would seem that the moral virtues belong to the contemplative life.
Objection 2. Further, the contemplative life is chiefly directed to the contemplation of God; for Gregory says (Hom. xiv in Ezech.) that "the mind tramples on all cares and longs to gaze on the face of its Creator." Now no one can accomplish this without cleanness of heart, which is a result of moral virtue [Cf. 08, 07]. For it is written (Matthew 5:8): "Blessed are the clean of heart, for they shall see God": and (Hebrews 12:14): "Follow peace with all men, and holiness, without which no man shall see God." Therefore it would seem that the moral virtues pertain to the contemplative life.
Objection 3. Further, Gregory says (Hom. xiv in Ezech.) that "the contemplative life gives beauty to the soul," wherefore it is signified by Rachel, of whom it is said (Genesis 29:17) that she was "of a beautiful countenance." Now the beauty of the soul consists in the moral virtues, especially temperance, as Ambrose says (De Offic. i, 43,45,46). Therefore it seems that the moral virtues pertain to the contemplative life.
On the contrary, The moral virtues are directed to external actions. Now Gregory says (Moral. vi [Hom. xiv in Ezech.; Cf. 1, Objection 3) that it belongs to the contemplative life "to rest from external action." Therefore the moral virtues do not pertain to the contemplative life.
I answer that, A thing may belong to the contemplative life in two ways, essentially or dispositively. The moral virtues do not belong to the contemplative life essentially, because the end of the contemplative life is the consideration of truth: and as the Philosopher states (Ethic. ii, 4), "knowledge," which pertains to the consideration of truth, "has little influence on the moral virtues": wherefore he declares (Ethic. x, 8) that the moral virtues pertain to active but not to contemplative happiness.
On the other hand, the moral virtues belong to the contemplative life dispositively. For the act of contemplation, wherein the contemplative life essentially consists, is hindered both by the impetuosity of the passions which withdraw the soul's intention from intelligible to sensible things, and by outward disturbances. Now the moral virtues curb the impetuosity of the passions, and quell the disturbance of outward occupations. Hence moral virtues belong dispositively to the contemplative life.
Reply to Objection 1. As stated above (Article 1), the contemplative life has its motive cause on the part of the affections, and in this respect the love of God and our neighbor is requisite to the contemplative life. Now motive causes do not enter into the essence of a thing, but dispose and perfect it. Wherefore it does not follow that the moral virtues belong essentially to the contemplative life.
Reply to Objection 2. Holiness or cleanness of heart is caused by the virtues that are concerned with the passions which hinder the purity of the reason; and peace is caused by justice which is about operations, according to Isaiah 32:17, "The work of justice shall be peace": since he who refrains from wronging others lessens the occasions of quarrels and disturbances. Hence the moral virtues dispose one to the contemplative life by causing peace and cleanness of heart.
Reply to Objection 3. Beauty, as stated above (Question 145, Article 2), consists in a certain clarity and due proportion. Now each of these is found radically in the reason; because both the light that makes beauty seen, and the establishing of due proportion among things belong to reason. Hence since the contemplative life consists in an act of the reason, there is beauty in it by its very nature and essence; wherefore it is written (Wisdom 8:2) of the contemplation of wisdom: "I became a lover of her beauty."
On the other hand, beauty is in the moral virtues by participation, in so far as they participate in the order of reason; and especially is it in temperance, which restrains the concupiscences which especially darken the light of reason. Hence it is that the virtue of chastity most of all makes man apt for contemplation, since venereal pleasures most of all weigh the mind down to sensible objects, as Augustine says (Soliloq. i, 10).
Source: Summa Theologica (New Advent)