Thomas Aquinas, Disputed Questions on Truth (De Veritate)

1. Before we can understand an accident inhering in a substance, we must understand the substance in the existence of a supposite. But by the union of the human nature with the Word the human nature is established in the existence of a supposite. Since grace is an accident, it seems that the union of the human nature with the Word must be understood before grace. Thus grace is not required for the union.

2. Human nature is capable of being assumed by the Word inasmuch as it is rational. And it does not get this from grace. Then it is not disposed for the union by grace.

3. The soul is infused into the body in order that in it the soul may be perfected with knowledge and virtues, as the Master makes clear. But Christ's soul is united to the Word before it is to the body; otherwise it would follow that a supposite was assumed, for from the union of the soul with the body a supposite is constituted. The union of Christ's soul with the Word must therefore be understood before we understand grace in it. Thus grace does not dispose for the union in question.

4. Between the nature and the supposite no accident intervenes. But the human nature is united to the Word as to a supposite. Grace therefore does not intervene there as a disposing medium.

5. The human nature is united to the Word not only as regards the soul but also as regards the body. Now the body is not capable of receiving grace. Consequently for the union of human nature to the Word grace is not needed as an intervening disposition.

6. As Augustine says, in miraculous occurrences "the whole reason for the miracle is the power of the miracle-worker." But the union of human nature to the divine is a miraculous occurrence above all others. It is therefore not necessary to posit a disposition on the part of the miracle, but the power of the miracle-worker suffices. Thus no intervening grace is required.

To the Contrary:

1'. Augustine says that whatever belongs to the Son of God by nature belongs to the Son of Man by grace. But it belongs to the Son of God by nature to be God. This also belongs to the Son of Man, then, by grace. But this belongs to Him through the union. Therefore grace is required for the union.

2'. Union in person is more excellent than union through fruition. But grace is required for the latter union. Then so is it for the former.

REPLY:

The proposition that habitual grace is required for the union in question can be understood in two ways: (1) It is required as a principle causing the union. To hold that the union in Christ is brought about by grace in this sense smacks of the heresy of Nestorius, who held that the humanity is united to the Word in Christ in no other way than on the basis of a perfect likeness in grace. (2) It is required as a disposition. This in turn can be of two kinds: either necessary or suitable--necessary, as heat or rarity is a disposition necessary for the form of fire, because matter cannot be the proper matter for fire unless it is taken together with heat and rarity; or suitable, as beauty is a disposition suitable for marriage.

Some therefore say that habitual grace is a necessary disposition, as making human nature capable of being assumed. But that does not seem to be true. For grace is rather the end of that assumption than a disposition for it. Damascene says that Christ assumed human nature in order to cure it. But that curing is accomplished through grace. Habitual grace in Christ is accordingly to be understood rather as an effect of the union than as a preparation for that union. This is indicated in the words of John (1:14): "We saw him as it were the only begotten of the Father, full of grace and truth," as if the fullness of grace belongs to Him by the very fact that He is the Only-begotten of the Father through the union.

Thus habitual grace is not to be understood as a disposition for the union except as suitable. In this sense habitual grace can be called the grace of union, though more fittingly and more in conformity with the meaning of the saints the grace of union is understood as the very existence in the person of the Word, which is conferred upon the human nature without any previous merits; but for this, habitual grace is not required as it is for the fruition, which consists in an operation; for a habit is not a principle of being but of operating.

Answers to Difficulties:

These are obvious from what has just been said.