Objection 1. It would seem that the virtues in one same man are not all equally intense. For the Apostle says (1 Corinthians 7:7): "Everyone hath his proper gift from God; one after this manner, and another after that." Now one gift would not be more proper than another to a man, if God infused all the virtues equally into each man. Therefore it seems that the virtues are not all equal in one and the same man.
Objection 2. Further, if all the virtues were equally intense in one and the same man, it would follow that whoever surpasses another in one virtue, would surpass him in all the others. But this is clearly not the case: since various saints are specially praised for different virtues; e.g. Abraham for faith (Romans 4), Moses for his meekness (Numbers 7:3), Job for his patience (Tobit 2:12). This is why of each Confessor the Church sings: "There was not found his like in keeping the law of the most High," [See Lesson in the Mass Statuit (Dominican Missal)], since each one was remarkable for some virtue or other. Therefore the virtues are not all equal in one and the same man.
Objection 3. Further, the more intense a habit is, the greater one's pleasure and readiness in making use of it. Now experience shows that a man is more pleased and ready to make use of one virtue than of another. Therefore the virtues are not all equal in one and the same man.
On the contrary, Augustine says (De Trin. vi, 4) that "those who are equal in fortitude are equal in prudence and temperance," and so on. Now it would not be so, unless all the virtues in one man were equal. Therefore all virtues are equal in one man.
I answer that, As explained above (Article 1), the comparative greatness of virtues can be understood in two ways. First, as referring to their specific nature: and in this way there is no doubt that in a man one virtue is greater than another, for example, charity, than faith and hope. Secondly, it may be taken as referring to the degree of participation by the subject, according as a virtue becomes intense or remiss in its subject. In this sense all the virtues in one man are equal with an equality of proportion, in so far as their growth in man is equal: thus the fingers are unequal in size, but equal in proportion, since they grow in proportion to one another.
Now the nature of this equality is to be explained in the same way as the connection of virtues; for equality among virtues is their connection as to greatness. Now it has been stated above (Question 65, Article 1) that a twofold connection of virtues may be assigned. The first is according to the opinion of those who understood these four virtues to be four general properties of virtues, each of which is found together with the other in any matter. In this way virtues cannot be said to be equal in any matter unless they have all these properties equal. Augustine alludes to this kind of equality (De Trin. vi, 4) when he says: "If you say these men are equal in fortitude, but that one is more prudent than the other; it follows that the fortitude of the latter is less prudent. Consequently they are not really equal in fortitude, since the former's fortitude is more prudent. You will find that this applies to the other virtues if you run over them all in the same way."
The other kind of connection among virtues followed the opinion of those who hold these virtues to have their own proper respective matters (65, A1,2). In this way the connection among moral virtues results from prudence, and, as to the infused virtues, from charity, and not from the inclination, which is on the part of the subject, as stated above (Question 65, Article 1). Accordingly the nature of the equality among virtues can also be considered on the part of prudence, in regard to that which is formal in all the moral virtues: for in one and the same man, so long as his reason has the same degree of perfection, the mean will be proportionately defined according to right reason in each matter of virtue.
But in regard to that which is material in the moral virtues, viz. the inclination to the virtuous act, one may be readier to perform the act of one virtue, than the act of another virtue, and this either from nature, or from habituation, or again by the grace of God.
Reply to Objection 1. This saying of the Apostle may be taken to refer to the gifts of gratuitous grace, which are not common to all, nor are all of them equal in the one same subject. We might also say that it refers to the measure of sanctifying grace, by reason of which one man has all the virtues in greater abundance than another man, on account of his greater abundance of prudence, or also of charity, in which all the infused virtues are connected.
Reply to Objection 2. One saint is praised chiefly for one virtue, another saint for another virtue, on account of his more admirable readiness for the act of one virtue than for the act of another virtue.
This suffices for the Reply to the Third Objection.
Source: Summa Theologica (New Advent)