On the contrary, Augustine says (De Trin. i, 10) that "man is in the Son of God, more than the Son in the Father." But the Son is in the Father by unity of essence, and man is in the Son by the union of the Incarnation. Therefore the union of the Incarnation is greater than the unity of the Divine Essence, which nevertheless is the greatest union; and thus the union of the Incarnation implies the greatest unity.
I answer that, Union implies the joining of several in some one thing. Therefore the union of the Incarnation may be taken in two ways: first, in regard to the things united; secondly, in regard to that in which they are united. And in this regard this union has a pre-eminence over other unions; for the unity of the Divine Person, in which the two natures are united, is the greatest. But it has no pre-eminence in regard to the things united.
Reply to Objection 1: The unity of the Divine Person is greater than numerical unity, which is the principle of number. For the unity of a Divine Person is an uncreated and self-subsisting unity, not received into another by participation. Also, it is complete in itself, having in itself whatever pertains to the nature of unity; and therefore it is not compatible with the nature of a part, as in numerical unity, which is a part of number, and which is shared in by the things numbered. And hence in this respect the union of the Incarnation is higher than numerical unity by reason of the unity of the Divine Person, and not by reason of the human nature, which is not the unity of the Divine Person, but is united to it.
Reply to Objection 2: This reason regards the things united, and not the Person in Whom the union takes place.
Reply to Objection 3: The unity of the Divine Person is greater than the unity of person and nature in us; and hence the union of the Incarnation is greater than the union of soul and body in us.
And because what is urged in the argument "on the contrary" rests upon what is untrue---namely, that the union of the Incarnation is greater than the unity of the Divine Persons in Essence---we must say to the authority of Augustine that the human nature is not more in the Son of God than the Son of God in the Father, but much less. But the man in some respects is more in the Son than the Son in the Father---namely, inasmuch as the same suppositum is signified when I say "man," meaning Christ, and when I say "Son of God"; whereas it is not the same suppositum of Father and Son.
Whether the union of the Incarnation took place by grace?
Objection 1: It would seem that the union of the Incarnation did not take place by grace. For grace is an accident, as was shown above (FS, Q[110], A[2]). But the union of the human nature to the Divine did not take place accidentally, as was shown above (A[6]). Therefore it seems that the union of the Incarnation did not take place by grace.
Objection 2: Further, the subject of grace is the soul. But it is written ( Col. 2:9 ): "In Christ [Vulg.: 'Him'] dwelleth all the fulness of the Godhead corporeally." Therefore it seems that this union did not take place by grace.
Objection 3: Further, every saint is united to God by grace. If, therefore, the union of the Incarnation was by grace, it would seem that Christ is said to be God no more than other holy men.
On the contrary, Augustine says (De Praed. Sanct. xv): "By the same grace every man is made a Christian, from the beginning of his faith, as this man from His beginning was made Christ." But this man became Christ by union with the Divine Nature. Therefore this union was by grace.
I answer that, As was said above (FS, Q[110], A[1]), grace is taken in two ways:--first, as the will of God gratuitously bestowing something; secondly, as the free gift of God. Now human nature stands in need of the gratuitous will of God in order to be lifted up to God, since this is above its natural capability. Moreover, human nature is lifted up to God in two ways: first, by operation, as the saints know and love God; secondly, by personal being, and this mode belongs exclusively to Christ, in Whom human nature is assumed so as to be in the Person of the Son of God. But it is plain that for the perfection of operation the power needs to be perfected by a habit, whereas that a nature has being in its own suppositum does not take place by means of a habit.
And hence we must say that if grace be understood as the will of God gratuitously doing something or reputing anything as well-pleasing or acceptable to Him, the union of the Incarnation took place by grace, even as the union of the saints with God by knowledge and love. But if grace be taken as the free gift of God, then the fact that the human nature is united to the Divine Person may be called a grace, inasmuch as it took place without being preceded by any merits---but not as though there were an habitual grace, by means of which the union took place.
Reply to Objection 1: The grace which is an accident is a certain likeness of the Divinity participated by man. But by the Incarnation human nature is not said to have participated a likeness of the Divine nature, but is said to be united to the Divine Nature itself in the Person of the Son. Now the thing itself is greater than a participated likeness of it.
Reply to Objection 2: Habitual grace is only in the soul; but the grace, i.e. the free gift of God, of being united to the Divine Person belongs to the whole human nature, which is composed of soul and body. And hence it is said that the fulness of the Godhead dwelt corporeally in Christ because the Divine Nature is united not merely to the soul, but to the body also. Although it may also be said that it dwelt in Christ corporeally, i.e. not as in a shadow, as it dwelt in the sacraments of the old law, of which it is said in the same place ( Col. 2:17 ) that they are the "shadow of things to come but the body is Christ" [Vulg.: 'Christ's'], inasmuch as the body is opposed to the shadow. And some say that the Godhead is said to have dwelt in Christ corporeally, i.e. in three ways, just as a body has three dimensions: first, by essence, presence, and power, as in other creatures; secondly, by sanctifying grace, as in the saints; thirdly, by personal union, which is proper to Christ.
Hence the reply to the third is manifest, viz. because the union of the Incarnation did not take place by habitual grace alone, but in subsistence or person.
Whether any merits preceded the union of the Incarnation?
Objection 1: It would seem that the union of the Incarnation followed upon certain merits, because upon Ps. 32:22, "Let Thy mercy, o Lord, be upon us, as," etc. a gloss says: "Here the prophet's desire for the Incarnation and its merited fulfilment are hinted at." Therefore the Incarnation falls under merit.
Objection 2: Further, whoever merits anything merits that without which it cannot be. But the ancient Fathers merited eternal life, to which they were able to attain only by the Incarnation; for Gregory says (Moral. xiii): "Those who came into this world before Christ's coming, whatsoever eminency of righteousness they may have had, could not, on being divested of the body, at once be admitted into the bosom of the heavenly country, seeing that He had not as yet come Who, by His own descending, should place the souls of the righteous in their everlasting seat." Therefore it would seem that they merited the Incarnation.
Objection 3: Further, of the Blessed Virgin it is sung that "she merited to bear the Lord of all" [*Little Office of B. V. M., Dominican Rite, Ant. at Benedictus], and this took place through the Incarnation. Therefore the Incarnation falls under merit.
On the contrary, Augustine says (De Praed. Sanct. xv): "Whoever can find merits preceding the singular generation of our Head, may also find merits preceding the repeated regeneration of us His members." But no merits preceded our regeneration, according to Titus 3:5 : "Not by the works of justice which we have done, but according to His mercy He saved us, by the laver of regeneration." Therefore no merits preceded the generation of Christ.
I answer that, With regard to Christ Himself, it is clear from the above (A[10]) that no merits of His could have preceded the union. For we do not hold that He was first of all a mere man, and that afterwards by the merits of a good life it was granted Him to become the Son of God, as Photinus held; but we hold that from the beginning of His conception this man was truly the Son of God, seeing that He had no other hypostasis but that of the Son of God, according to Luke 1:35 : "The Holy which shall be born of thee shall be called the Son of God." And hence every operation of this man followed the union. Therefore no operation of His could have been meritorious of the union.
Neither could the needs of any other man whatsoever have merited this union condignly: first, because the meritorious works of man are properly ordained to beatitude, which is the reward of virtue, and consists in the full enjoyment of God. Whereas the union of the Incarnation, inasmuch as it is in the personal being, transcends the union of the beatified mind with God, which is by the act of the soul in fruition; and therefore it cannot fall under merit. Secondly, because grace cannot fall under merit, for the principle of merit does not fall under merit; and therefore neither does grace, for it is the principle of merit. Hence, still less does the Incarnation fall under merit, since it is the principle of grace, according to Jn. 1:17 : "Grace and truth came by Jesus Christ." Thirdly, because the Incarnation is for the reformation of the entire human nature, and therefore it does not fall under the merit of any individual man, since the goodness of a mere man cannot be the cause of the good of the entire nature. Yet the holy Fathers merited the Incarnation congruously by desiring and beseeching; for it was becoming that God should harken to those who obeyed Him.
And thereby the reply to the First Objection is manifest.
Reply to Objection 2: It is false that under merit falls everything without which there can be no reward. For there is something pre-required not merely for reward, but also for merit, as the Divine goodness and grace and the very nature of man. And again, the mystery of the Incarnation is the principle of merit, because "of His fulness we all have received" ( Jn. 1:16 ).