Objection 1. It would seem that these four virtues are unfittingly divided into exemplar virtues, perfecting virtues, perfect virtues, and social virtues. For as Macrobius says (Super Somn. Scip. 1), the "exemplar virtues are such as exist in the mind of God." Now the Philosopher says (Ethic. x, 8) that "it is absurd to ascribe justice, fortitude, temperance, and prudence to God." Therefore these virtues cannot be exemplar.
Objection 2. Further, the "perfect" virtues are those which are without any passion: for Macrobius says (Super Somn. Scip. 1) that "in a soul that is cleansed, temperance has not to check worldly desires, for it has forgotten all about them: fortitude knows nothing about the passions; it does not have to conquer them." Now it was stated above (Question 59, Article 5) that the aforesaid virtues cannot be without passions. Therefore there is no such thing as "perfect" virtue.
Objection 3. Further, he says (Macrobius: Super Somn. Scip. 1) that the "perfecting" virtues are those of the man "who flies from human affairs and devotes himself exclusively to the things of God." But it seems wrong to do this, for Cicero says (De Offic. i): "I reckon that it is not only unworthy of praise, but wicked for a man to say that he despises what most men admire, viz. power and office." Therefore there are no "perfecting" virtues.
Objection 4. Further, he says (Macrobius: Super Somn. Scip. 1) that the "social" virtues are those "whereby good men work for the good of their country and for the safety of the city." But it is only legal justice that is directed to the common weal, as the Philosopher states (Ethic. v, 1). Therefore other virtues should not be called "social."
On the contrary, Macrobius says (Super Somn. Scip. 1): "Plotinus, together with Plato foremost among teachers of philosophy, says: 'The four kinds of virtue are fourfold: In the first place there are social virtues; secondly, there are perfecting virtues; thirdly, there are perfect virtues; and fourthly, there are exemplar virtues.'"
I answer that, As Augustine says (De Moribus Eccl. vi), "the soul needs to follow something in order to give birth to virtue: this something is God: if we follow Him we shall live aright." Consequently the exemplar of human virtue must needs pre-exist in God, just as in Him pre-exist the types of all things. Accordingly virtue may be considered as existing originally in God, and thus we speak of "exemplar" virtues: so that in God the Divine Mind itself may be called prudence; while temperance is the turning of God's gaze on Himself, even as in us it is that which conforms the appetite to reason. God's fortitude is His unchangeableness; His justice is the observance of the Eternal Law in His works, as Plotinus states (Cf. Macrobius, Super Somn. Scip. 1).
Again, since man by his nature is a social [See above note on Chrysostom] animal, these virtues, in so far as they are in him according to the condition of his nature, are called "social" virtues; since it is by reason of them that man behaves himself well in the conduct of human affairs. It is in this sense that we have been speaking of these virtues until now.
But since it behooves a man to do his utmost to strive onward even to Divine things, as even the Philosopher declares in Ethic. x, 7, and as Scripture often admonishes us--for instance: "Be ye... perfect, as your heavenly Father is perfect" (Matthew 5:48), we must needs place some virtues between the social or human virtues, and the exemplar virtues which are Divine. Now these virtues differ by reason of a difference of movement and term: so that some are virtues of men who are on their way and tending towards the Divine similitude; and these are called "perfecting" virtues. Thus prudence, by contemplating the things of God, counts as nothing all things of the world, and directs all the thoughts of the soul to God alone: temperance, so far as nature allows, neglects the needs of the body; fortitude prevents the soul from being afraid of neglecting the body and rising to heavenly things; and justice consists in the soul giving a whole-hearted consent to follow the way thus proposed. Besides these there are the virtues of those who have already attained to the Divine similitude: these are called the "perfect virtues." Thus prudence sees nought else but the things of God; temperance knows no earthly desires; fortitude has no knowledge of passion; and justice, by imitating the Divine Mind, is united thereto by an everlasting covenant. Such as the virtues attributed to the Blessed, or, in this life, to some who are at the summit of perfection.
Reply to Objection 1. The Philosopher is speaking of these virtues according as they relate to human affairs; for instance, justice, about buying and selling; fortitude, about fear; temperance, about desires; for in this sense it is absurd to attribute them to God.
Reply to Objection 2. Human virtues, that is to say, virtues of men living together in this world, are about the passions. But the virtues of those who have attained to perfect bliss are without passions. Hence Plotinus says (Cf. Macrobius, Super Somn. Scip. 1) that "the social virtues check the passions," i.e. they bring them to the relative mean; "the second kind," viz. the perfecting virtues, "uproot them"; "the third kind," viz. the perfect virtues, "forget them; while it is impious to mention them in connection with virtues of the fourth kind," viz. the exemplar virtues. It may also be said that here he is speaking of passions as denoting inordinate emotions.
Reply to Objection 3. To neglect human affairs when necessity forbids is wicked; otherwise it is virtuous. Hence Cicero says a little earlier: "Perhaps one should make allowances for those who by reason of their exceptional talents have devoted themselves to learning; as also to those who have retired from public life on account of failing health, or for some other yet weightier motive; when such men yielded to others the power and renown of authority." This agrees with what Augustine says (De Civ. Dei xix, 19): "The love of truth demands a hollowed leisure; charity necessitates good works. If no one lays this burden on us we may devote ourselves to the study and contemplation of truth; but if the burden is laid on us it is to be taken up under the pressure of charity."
Reply to Objection 4. Legal justice alone regards the common weal directly: but by commanding the other virtues it draws them all into the service of the common weal, as the Philosopher declares (Ethic. v, 1). For we must take note that it concerns the human virtues, as we understand them here, to do well not only towards the community, but also towards the parts of the community, viz. towards the household, or even towards one individual.
Source: Summa Theologica (New Advent)