We proceed to the second article thus:
1. It seems that grace is not a quality of the soul. No quality acts on the subject to which it belongs. If it did, the subject would have to act on itself, since there is no action of a quality without the action of its subject. But grace acts on the soul, in justifying it. It follows that grace is not a quality.
2. Again, a substance is nobler than its quality. But grace is nobler than the soul's nature, since we can do many things by grace which we cannot do by nature, as was said in Q.109, Arts.1, 2, and 3. It follows that grace is not a quality.
3. Again, no quality persists after it ceases to be in its subject. But grace persists, since it is not corrupted. If grace were corrupted it would be reduced to nothing, since it is created out of nothing -- wherefore it is called a "new creature" in Galatians. It follows that grace is not a quality.
On the other hand: the gloss by Augustine on Ps.104:15, "Oil to make his face to shine," says that "grace is a beauty of the soul, which wins the divine love." Beauty of soul is a quality, just as comeliness of body is a quality. It follows that grace is a quality.
I answer: as we maintained in the preceding article, to say that a man has the grace of God is to say that there is within him an effect of God's gracious will. Now God's gracious will helps a man in two ways, as we said in Q.109, Art.1. In the first place, a man's mind is helped by God to know, to will, or to act. Such an effect of grace is not a quality, but a movement of the soul, since "in the moved, the act of the mover is a movement," as is said in 3 Physics, text 18. Secondly, God infuses a habitual gift into the soul, for the reason that it would not be fitting that God should give less to those whom he loves in order that they may attain supernatural good, than he gives to creatures whom he loves in order that they may attain only natural good. Now God provides for natural creatures not only by moving them to their natural actions, but by endowing them with forms and powers which are the principles of actions, so that they may incline to such movements of their own accord. In this way the movements to which God moves them become natural to creatures, and easy for them, in accordance with Wisdom 8:1: ". . . and disposes all things sweetly." Much more, then, does God infuse certain forms or supernatural qualities into those whom he moves to seek after supernatural and eternal good, that they may be thus moved by him to seek it sweetly and readily. The gift of grace, therefore, is a certain quality.
On the first point: as a quality, grace is said to act on the soul not as an efficient cause, but as a formal cause, as whiteness makes things white, or as justice makes things just.
On the second point: any substance is either the nature of that of which it is the substance, or a part of its nature. In this sense, matter and form are both called "substance." But grace is higher than human nature. It cannot then be its substance, nor yet the form of its substance. Grace is a form accidental to the soul. What exists as substance in God occurs as accident in the soul which shares in divine good, as is obvious in the case of knowledge. But since the soul shares in divine good imperfectly, this participation itself, which is grace, exists in the soul in a less perfect mode than that in which the soul exists in itself. Such grace is nevertheless nobler than the soul's nature, in so far as it is an expression or sharing of the divine goodness, even though it is not nobler than the soul in respect of its mode of being.
On the third point: as Boethius says (Isagogue Porphyri): "the being of an accident is to inhere." Thus an accident is said to "be," not as if it existed by itself, but because some subject "is" through possessing it. It is thus affirmed of an existence, rather than affirmed to be an existence, as is said in 7 Metaph., text 2. Now since coming to be and passing away are affirmed of what exists, properly speaking no accident comes to be or passes away. But an accident is said to come to be or to pass away when its subject begins or ceases to be actualized through possession of it. In this sense, grace is said to be created when it is men who are created in grace, i.e., when they are created anew out of nothing, and not on account of merit, according to Eph.2:10: "created in Christ Jesus unto good works."