Objection 1. It would seem that the first man was not created in grace. For the Apostle, distinguishing between Adam and Christ, says (1 Corinthians 15:45): "The first Adam was made into a living soul; the last Adam into a quickening spirit." But the spirit is quickened by grace. Therefore Christ alone was made in grace.
Objection 2. Further, Augustine says (QQ. Vet. et Nov. Test., qu. 123) [Work of an anonymous author, among the supposititious works of St. Augustine] that "Adam did not possess the Holy Ghost." But whoever possesses grace has the Holy Ghost. Therefore Adam was not created in grace.
Objection 3. Further, Augustine says (De Correp. et Grat. x) that "God so ordered the life of the angels and men, as to show first what they could do by free-will, then what they could do by His grace, and by the discernment of righteousness." God thus first created men and angels in the state of natural free-will only; and afterwards bestowed grace on them.
Objection 4. Further, the Master says (Sent. ii, D, xxiv): "When man was created he was given sufficient help to stand, but not sufficient to advance." But whoever has grace can advance by merit. Therefore the first man was not created in grace.
Objection 5. Further, the reception of grace requires the consent of the recipient, since thereby a kind of spiritual marriage takes place between God and the soul. But consent presupposes existence. Therefore man did not receive grace in the first moment of his creation.
Objection 6. Further, nature is more distant from grace than grace is from glory, which is but grace consummaed. But in man grace precedes glory. Therefore much more did nature precede grace.
On the contrary, Man and angel are both ordained to grace. But the angels were created in grace, for Augustine says (De Civ. Dei xii, 9): "God at the same time fashioned their nature and endowed them with grace." Therefore man also was created in grace.
I answer that, Some say that man was not created in grace; but that it was bestowed on him subsequently before sin: and many authorities of the Saints declare that man possessed grace in the state of innocence.
But the very rectitude of the primitive state, wherewith man was endowed by God, seems to require that, as others say, he was created in grace, according to Ecclesiastes 7:30, "God made man right." For this rectitude consisted in his reason being subject to God, the lower powers to reason, and the body to the soul: and the first subjection was the cause of both the second and the third; since while reason was subject to God, the lower powers remained subject to reason, as Augustine says [Cf. De Civ. Dei xiii, 13; De Pecc. Merit. et Remiss. i, 16. Now it is clear that such a subjection of the body to the soul and of the lower powers to reason, was not from nature; otherwise it would have remained after sin; since even in the demons the natural gifts remained after sin, as Dionysius declared (Div. Nom. iv). Hence it is clear that also the primitive subjection by virtue of which reason was subject to God, was not a merely natural gift, but a supernatural endowment of grace; for it is not possible that the effect should be of greater efficiency than the cause. Hence Augustine says (De Civ. Dei xiii, 13) that, "as soon as they disobeyed the Divine command, and forfeited Divine grace, they were ashamed of their nakedness, for they felt the impulse of disobedience in the flesh, as though it were a punishment corresponding to their own disobedience." Hence if the loss of grace dissolved the obedience of the flesh to the soul, we may gather that the inferior powers were subjected to the soul through grace existing therein.
Reply to Objection 1. The Apostle in these words means to show that there is a spiritual body, if there is an animal body, inasmuch as the spiritual life of the body began in Christ, who is "the firstborn of the dead," as the body's animal life began in Adam. From the Apostle's words, therefore, we cannot gather that Adam had no spiritual life in his soul; but that he had not spiritual life as regards the body.
Reply to Objection 2. As Augustine says in the same passage, it is not disputed that Adam, like other just souls, was in some degree gifted with the Holy Ghost; but "he did not possess the Holy Ghost, as the faithful possess Him now," who are admitted to eternal happiness directly after death.
Reply to Objection 3. This passage from Augustine does not assert that angels or men were created with natural free-will before they possessed grace; but that God shows first what their free-will could do before being confirmed in grace, and what they acquired afterwards by being so confirmed.
Reply to Objection 4. The Master here speaks according to the opinion of those who held that man was not created in grace, but only in a state of nature. We may also say that, though man was created in grace, yet it was not by virtue of the nature wherein he was created that he could advance by merit, but by virtue of the grace which was added.
Reply to Objection 5. As the motion of the will is not continuous there is nothing against the first man having consented to grace even in the first moment of his existence.
Reply to Objection 6. We merit glory by an act of grace; but we do not merit grace by an act of nature; hence the comparison fails.
Source: Summa Theologica (New Advent)