Now since all perfection and greatness must be attributed to Christ, consequently He must have by merit what others have by merit; unless it be of such a nature that its want would detract from Christ's dignity and perfection more than would accrue to Him by merit. Hence He merited neither grace nor knowledge nor the beatitude of His soul, nor the Godhead, because, since merit regards only what is not yet possessed, it would be necessary that Christ should have been without these at some time; and to be without them would have diminished Christ's dignity more than His merit would have increased it. But the glory of the body, and the like, are less than the dignity of meriting, which pertains to the virtue of charity. Hence we must say that Christ had, by merit, the glory of His body and whatever pertained to His outward excellence, as His Ascension, veneration, and the rest. And thus it is clear that He could merit for Himself.
Reply Obj. 1: Fruition, which is an act of charity, pertains to the glory of the soul, which Christ did not merit. Hence if He merited by charity, it does not follow that the merit and the reward are the same. Nor did He merit by charity inasmuch as it was the charity of a comprehensor, but inasmuch as it was that of a wayfarer. For He was at once a wayfarer and a comprehensor, as was said above (Q. 15, A. 10). And therefore, since He is no longer a wayfarer, He is not in the state of meriting.
Reply Obj. 2: Because by nature Christ is God and the Son of God, the Divine glory and the lordship of all things are due to Him, as to the first and supreme Lord. Nevertheless a glory is due to Him as a beatified man; and this He has partly without merit, and partly with merit, as is clear from what has been said.
Reply Obj. 3: It is by Divine appointment that there is an overflow of glory from the soul to the body, in keeping with human merit; so that as man merits by the act of the soul which he performs in the body, so he may be rewarded by the glory of the soul overflowing to the body. And hence not only the glory of the soul, but also the glory of the body falls under merit, according to Rom. 8:11: "He . . . shall quicken also our [Vulg.: 'your'] mortal bodies, because of His Spirit that dwelleth in us [Vulg.: 'you']." And thus it could fall under Christ's merit.
Reply Obj. 4: The manifestation of Christ's excellence is His good as regards the being which it has in the knowledge of others; although in regard to the being which they have in themselves it chiefly belongs to the good of those who know Him. Yet even this is referred to Christ inasmuch as they are His members. _______________________
FOURTH ARTICLE [III, Q. 19, Art. 4]
Whether Christ Could Merit for Others?
Objection 1: It would seem that Christ could not merit for others. For it is written (Ezech. 18:4): "The soul that sinneth, the same shall die." Hence, for a like reason, the soul that meriteth, the same shall be recompensed. Therefore it is not possible that Christ merited for others.
Obj. 2: Further, of the fulness of Christ's grace we all receive, as is written John 1:16. Now other men having Christ's grace cannot merit for others. For it is written (Ezech. 14:20) that if "Noe and Daniel and Job be in the city [Vulg.: 'the midst thereof'] . . . they shall deliver neither son nor daughter; but they shall only deliver their own souls by their justice." Hence Christ could not merit anything for us.
Obj. 3: Further, the "reward" that we merit is due "according to justice [Vulg.: 'debt'] and not according to grace," as is clear from Rom. 4:4. Therefore if Christ merited our salvation it follows that our salvation is not by God's grace but by justice, and that He acts unjustly with those whom He does not save, since Christ's merit extends to all.