Objection 1. It would seem that wisdom is not the greatest of the intellectual virtues. Because the commander is greater than the one commanded. Now prudence seems to command wisdom, for it is stated in Ethic. i, 2 that political science, which belongs to prudence (Ethic. vi, 8), "orders that sciences should be cultivated in states, and to which of these each individual should devote himself, and to what extent." Since, then, wisdom is one of the sciences, it seems that prudence is greater than wisdom.
Objection 2. Further, it belongs to the nature of virtue to direct man to happiness: because virtue is "the disposition of a perfect thing to that which is best," as stated in Phys. vii, text. 17. Now prudence is "right reason about things to be done," whereby man is brought to happiness: whereas wisdom takes no notice of human acts, whereby man attains happiness. Therefore prudence is a greater virtue than wisdom.
Objection 3. Further, the more perfect knowledge is, the greater it seems to be. Now we can have more perfect knowledge of human affairs, which are the subject of science, than of Divine things, which are the object of wisdom, which is the distinction given by Augustine (De Trin. xii, 14): because Divine things are incomprehensible, according to Job 26:26: "Behold God is great, exceeding our knowledge." Therefore science is a greater virtue than wisdom.
Objection 4. Further, knowledge of principles is more excellent than knowledge of conclusions. But wisdom draws conclusions from indemonstrable principles which are the object of the virtue of understanding, even as other sciences do. Therefore understanding is a greater virtue than wisdom.
On the contrary, The Philosopher says (Ethic. vi, 7) that wisdom is "the head" among "the intellectual virtues."
I answer that, As stated above (Article 3), the greatness of a virtue, as to its species, is taken from its object. Now the object of wisdom surpasses the objects of all the intellectual virtues: because wisdom considers the Supreme Cause, which is God, as stated at the beginning of the Metaphysics. And since it is by the cause that we judge of an effect, and by the higher cause that we judge of the lower effects; hence it is that wisdom exercises judgment over all the other intellectual virtues, directs them all, and is the architect of them all.
Reply to Objection 1. Since prudence is about human affairs, and wisdom about the Supreme Cause, it is impossible for prudence to be a greater virtue than wisdom, "unless," as stated in Ethic. vi, 7, "man were the greatest thing in the world." Wherefore we must say, as stated in the same book (Ethic. vi), that prudence does not command wisdom, but vice versa: because "the spiritual man judgeth all things; and he himself is judged by no man" (1 Corinthians 2:15). For prudence has no business with supreme matters which are the object of wisdom: but its command covers things directed to wisdom, viz. how men are to obtain wisdom. Wherefore prudence, or political science, is, in this way, the servant of wisdom; for it leads to wisdom, preparing the way for her, as the doorkeeper for the king.
Reply to Objection 2. Prudence considers the means of acquiring happiness, but wisdom considers the very object of happiness, viz. the Supreme Intelligible. And if indeed the consideration of wisdom were perfect in respect of its object, there would be perfect happiness in the act of wisdom: but as, in this life, the act of wisdom is imperfect in respect of its principal object, which is God, it follows that the act of wisdom is a beginning or participation of future happiness, so that wisdom is nearer than prudence to happiness.
Reply to Objection 3. As the Philosopher says (De Anima i, text. 1), "one knowledge is preferable to another, either because it is about a higher object, or because it is more certain." Hence if the objects be equally good and sublime, that virtue will be greater which possesses more certain knowledge. But a virtue which is less certain about a higher and better object, is preferable to that which is more certain about an object of inferior degree. Wherefore the Philosopher says (De Coelo ii, text. 60) that "it is a great thing to be able to know something about celestial beings, though it be based on weak and probable reasoning"; and again (De Part. Animal. i, 5) that "it is better to know a little about sublime things, than much about mean things." Accordingly wisdom, to which knowledge about God pertains, is beyond the reach of man, especially in this life, so as to be his possession: for this "belongs to God alone" (Metaph. i, 2): and yet this little knowledge about God which we can have through wisdom is preferable to all other knowledge.
Reply to Objection 4. The truth and knowledge of indemonstrable principles depends on the meaning of the terms: for as soon as we know what is a whole, and what is a part, we know at once that every whole is greater than its part. Now to know the meaning of being and non-being, of whole and part, and of other things consequent to being, which are the terms whereof indemonstrable principles are constituted, is the function of wisdom: since universal being is the proper effect of the Supreme Cause, which is God. And so wisdom makes use of indemonstrable principles which are the object of understanding, not only by drawing conclusions from them, as other sciences do, but also by passing its judgment on them, and by vindicating them against those who deny them. Hence it follows that wisdom is a greater virtue than understanding.
Source: Summa Theologica (New Advent)