Objection 1. It would seem that seven gifts of the Holy Ghost are unsuitably enumerated. For in that enumeration four are set down corresponding to the intellectual virtues, viz. wisdom, understanding, knowledge, and counsel, which corresponds to prudence; whereas nothing is set down corresponding to art, which is the fifth intellectual virtue. Moreover, something is included corresponding to justice, viz. piety, and something corresponding to fortitude, viz. the gift of fortitude; while there is nothing to correspond to temperance. Therefore the gifts are enumerated insufficiently.
Objection 2. Further, piety is a part of justice. But no part of fortitude is assigned to correspond thereto, but fortitude itself. Therefore justice itself, and not piety, ought to have been set down.
Objection 3. Further, the theological virtues, more than any, direct us to God. Since, then, the gifts perfect man according as he is moved by God, it seems that some gifts, corresponding to the theological virtues, should have been included.
Objection 4. Further, even as God is an object of fear, so is He of love, of hope, and of joy. Now love, hope, and joy are passions condivided with fear. Therefore, as fear is set down as a gift, so ought the other three.
Objection 5. Further, wisdom is added in order to direct understanding; counsel, to direct fortitude; knowledge, to direct piety. Therefore, some gift should have been added for the purpose of directing fear. Therefore the seven gifts of the Holy Ghost are unsuitably enumerated.
On the contrary, stands the authority of Holy Writ (Isaiah 11:2-3).
I answer that, As stated above (Article 3), the gifts are habits perfecting man so that he is ready to follow the promptings of the Holy Ghost, even as the moral virtues perfect the appetitive powers so that they obey the reason. Now just as it is natural for the appetitive powers to be moved by the command of reason, so it is natural for all the forces in man to be moved by the instinct of God, as by a superior power. Therefore whatever powers in man can be the principles of human actions, can also be the subjects of gifts, even as they are virtues; and such powers are the reason and appetite.
Now the reason is speculative and practical: and in both we find the apprehension of truth (which pertains to the discovery of truth), and judgment concerning the truth. Accordingly, for the apprehension of truth, the speculative reason is perfected by "understanding"; the practical reason, by "counsel." In order to judge aright, the speculative reason is perfected by "wisdom"; the practical reason by "knowledge." The appetitive power, in matters touching a man's relations to another, is perfected by "piety"; in matters touching himself, it is perfected by "fortitude" against the fear of dangers; and against inordinate lust for pleasures, by "fear," according to Proverbs 15:27: "By the fear of the Lord every one declineth from evil," and Psalm 118:120: "Pierce Thou my flesh with Thy fear: for I am afraid of Thy judgments." Hence it is clear that these gifts extend to all those things to which the virtues, both intellectual and moral, extend.
Reply to Objection 1. The gifts of the Holy Ghost perfect man in matters concerning a good life: whereas art is not directed to such matters, but to external things that can be made, since art is the right reason, not about things to be done, but about things to be made (Ethic. vi, 4). However, we may say that, as regards the infusion of the gifts, the art is on the part of the Holy Ghost, Who is the principal mover, and not on the part of men, who are His organs when He moves them. The gift of fear corresponds, in a manner, to temperance: for just as it belongs to temperance, properly speaking, to restrain man from evil pleasures for the sake of the good appointed by reason, so does it belong to the gift of fear, to withdraw man from evil pleasures through fear of God.
Reply to Objection 2. Justice is so called from the rectitude of the reason, and so it is more suitably called a virtue than a gift. But the name of piety denotes the reverence which we give to our father and to our country. And since God is the Father of all, the worship of God is also called piety, as Augustine states (De Civ. Dei x, 1). Therefore the gift whereby a man, through reverence for God, works good to all, is fittingly called piety.
Reply to Objection 3. The mind of man is not moved by the Holy Ghost, unless in some way it be united to Him: even as the instrument is not moved by the craftsman, unless there by contact or some other kind of union between them. Now the primal union of man with God is by faith, hope and charity: and, consequently, these virtues are presupposed to the gifts, as being their roots. Therefore all the gifts correspond to these three virtues, as being derived therefrom.
Reply to Objection 4. Love, hope and joy have good for their object. Now God is the Sovereign Good: wherefore the names of these passions are transferred to the theological virtues which unite man to God. On the other hand, the object of fear is evil, which can nowise apply to God: hence fear does not denote union with God, but withdrawal from certain things through reverence for God. Hence it does not give its name to a theological virtue, but to a gift, which withdraws us from evil, for higher motives than moral virtue does.
Reply to Objection 5. Wisdom directs both the intellect and the affections of man. Hence two gifts are set down as corresponding to wisdom as their directing principle; on the part of the intellect, the gift of understanding; on the part of the affections, the gift of fear. Because the principal reason for fearing God is taken from a consideration of the Divine excellence, which wisdom considers.
Source: Summa Theologica (New Advent)