Summa Th. III EN Qu.32 a.4
Objection: 1. It would seem that the Blessed Virgin cooperated actively in the conception of Christ's body. For Damascene says (De Fide Orth. iii) that "the Holy Ghost came upon the Virgin, purifying her, and bestowing on her the power to receive and to bring forth the Word of God." But she had from nature the passive power of generation, like any other woman. Therefore He bestowed on her an active power of generation. And thus she cooperated actively in Christ's conception.
2. Further, all the powers of the vegetative soul are active, as the Commentator says (De Anima ii). But the generative power, in both man and woman, belongs to the vegetative soul. Therefore, both in man and woman, it cooperates actively in the conception of the child.
3. Further, in the conception of a child the woman supplies the matter from which the child's body is naturally formed. But nature is an intrinsic principle of movement. Therefore it seems that in the very matter supplied by the Blessed Virgin there was an active principle.
On the contrary The active principle in generation is called the "seminal virtue." But, as Augustine says (Gn ad lit. x), Christ's body "was taken from the Virgin, only as to corporeal matter, by the Divine power of conception and formation, but not by any human seminal virtue." Therefore the Blessed Virgin did not cooperate actively in, the conception of Christ's body.
I answer that Some say that the Blessed Virgin cooperated actively in Christ's conception, both by natural and by a supernatural power. By natural power, because they hold that in all natural matter there is an active principle. otherwise they believe that there would be no such thing as natural transformation. But in this they are deceived. Because a transformation is said to be natural by reason not only of an active but also of a passive intrinsic principle: for the Philosopher says expressly (Phys. viii) that in heavy and light things there is a passive, and not an active, principle of natural movement. Nor is it possible for matter to be active in its own formation, since it is not in act. Nor, again, is it possible for anything to put itself in motion except it be divided into two parts, one being the mover, the other being moved: which happens in animate things only, as is proved Phys. viii.By a supernatural power, because they say that the mother requires not only to supply the matter, which is the menstrual blood, but also the semen, which, being mingled with that of the male, has an active power in generation. And since in the Blessed Virgin there was no resolution of semen, by reason of her inviolate virginity, they say that the Holy Ghost supernaturally bestowed on her an active power in the conception of Christ's body, which power other mothers have by reason of the semen resolved. But this cannot stand, because, since "each thing is on account of its operation" (De Coel. ii), nature would not, for the purpose of the act of generation, distinguish the male and female sexes, unless the action of the male were distinct from that of the female. Now, in generation there are two distinct operations---that of the agent and that of the patient. Wherefore it follows that the entire active operation is on the part of the male, and the passive on the part of the female. For this reason in plants, where both forces are mingled, there is no distinction of male and female.Since, therefore, the Blessed Virgin was not Christ's Father, but His Mother, it follows that it was not given to her to exercise an active power in His conception: whether to cooperate actively so as to be His Father, or not to cooperate at all, as some say. whence it would follow that this active power was bestowed on her to no purpose. We must therefore say that in Christ's conception itself she did not cooperate actively, but merely supplied the matter thereof. Nevertheless, before the conception she cooperated actively in the preparation of the matter so that it should be apt for the conception.
Reply to Objection: 1. This conception had three privileges---namely, that it was without original sin; that it was not that of a man only, but of God and man; and that it was a virginal conception. And all three were effected by the Holy Ghost. Therefore Damascene says, as to the first, that the Holy Ghost "came upon the Virgin, purifying her"---that is, preserving her from conceiving with original sin. As to the second, he says: "And bestowing on her the power to receive," i.e. to conceive, "the Word of God." As to the third, he says: "And to give birth" to Him, i.e. that she might, while remaining a virgin, bring Him forth, not actively, but passively, just as other mothers achieve this through the action of the male seed.
2. The generative power of the female is imperfect compared to that of the male. And, therefore, just as in the arts the inferior art gives a disposition to the matter to which the higher art gives the form, as is stated Phys. ii, so also the generative power of the female prepares the matter, which is then fashioned by the active power of the male.
3. In order for a transformation to be natural, there is no need for an active principle in matter, but only for a passive principle, as stated above.
We have now to consider the mode and order of Christ's conception, concerning which there are four points of inquiry:
(1) Whether Christ's body was formed in the first instant of its conception?
(2) Whether it was animated in the first instant of its conception?
(3) Whether it was assumed by the Word in the first instant of its conception?
(4) Whether this conception was natural or miraculous?
Objection: 1. It would seem that Christ's body was not formed in the first instant of its conception. For it is written (Jn 2,20): "Six-and-forty years was this Temple in building"; on which words Augustine comments as follows (De Trin. iv): "This number applies manifestly to the perfection of our Lord's body." He says, further (Questions. lxxxiii, qu. 56): "It is not without reason that the Temple, which was a type of His body, is said to have been forty-six years in building: so that as many years as it took to build the Temple, in so many days was our Lord's body perfected." Therefore Christ's body was not perfectly formed in the first instant of its conception.
2. Further, there was need of local movement for the formation of Christ's body in order that the purest blood of the Virgin's body might be brought where generation might aptly take place. Now, no body can be moved locally in an instant: since the time taken in movement is divided according to the division of the thing moved, as is proved Phys. vi. Therefore Christ's body was not formed in an instant.
3. Further, Christ's body was formed of the purest blood of the Virgin, as stated above (Question , Article ). But that matter could not be in the same instant both blood and flesh, because thus matter would have been at the same time the subject of two forms. Therefore the last instant in which it was blood was distinct from the first instant in which it was flesh. But between any two instants there is an interval of time. Therefore Christ's body was not formed in an instant, but during a space of time.
4. Further, as the augmentative power requires a fixed time for its act, so also does the generative power: for both are natural powers belonging to the vegetative soul. But Christ's body took a fixed time to grow, like the bodies of other men: for it is written (Lc 2,52) that He "advanced in wisdom and age." Therefore it seems for the same reason that the formation of His body, since that, too, belongs to the generative power, was not instantaneous, but took a fixed time, like the bodies of other men.
On the contrary Gregory says (Moral. xviii): "As soon as the angel announced it, as soon as the Spirit came down, the Word was in the womb, within the womb the Word was made flesh."
I answer that In the conception of Christ's body three points may be considered: first, the local movement of the blood to the place of generation; secondly, the formation of the body from that matter; thirdly, the development whereby it was brought to perfection of quantity. of these, the second is the conception itself; the first is a preamble; the third, a result of the conception.Now, the first could not be instantaneous: since this would be contrary to the very nature of the local movement of any body whatever, the parts of which come into a place successively. The third also requires a succession of time: both because there is no increase without local movement, and because increase is effected by the power of the soul already informing the body, the operation of which power is subject to time.But the body's very formation, in which conception principally consists, was instantaneous, for two reasons. First, because of the infinite power of the agent, viz. the Holy Ghost, by whom Christ's body was formed, as stated above (Question , Article ). For the greater the power of an agent, the more quickly can it dispose matter; and, consequently, an agent of infinite power can dispose matter instantaneously to its due form. Secondly, on the part of the Person of the Son, whose body was being formed. For it was unbecoming that He should take to Himself a body as yet unformed. While, if the conception had been going on for any time before the perfect formation of the body, the whole conception could not be attributed to the Son of God, since it is not attributed to Him except by reason of the assumption of that body. Therefore in the first instant in which the various parts of the matter were united together in the place of generation, Christ's body was both perfectly formed and assumed. And thus is the Son of God said to have been conceived; nor could it be said otherwise.
Reply to Objection: 1. Neither quotation from Augustine refers to formation alone of Christ's body, but to its formation, together with a fixed development up to the time of His birth. Wherefore in the aforesaid number are foreshadowed the number of months during which Christ was in the Virgin's womb.
2. This local movement is not comprised within the conception itself, but is a preamble thereto.
3. It is not possible to fix the last instant in which that matter was blood: but it is possible to fix the last period of time which continued without any interval up to the first instant in which Christ's body was formed. And this instant was the terminus of the time occupied by the local movement of the matter towards the place of generation.
4. Increase is caused by the augmentative power of that which is the subject of increase: but the formation of the body is caused by the generative power, not of that which is generated, but of the father generating from seed, in which the formative power derived from the father's soul has its operation. But Christ's body was not formed by the seed of man, as stated above (Question , Article , ad 3), but by the operation of the Holy Ghost. Therefore the formation thereof should be such as to be worthy of the Holy Ghost. But the development of Christ's body was the effect of the augmentative power in Christ's soul: and since this was of the same species as ours, it behooved His body to develop in the same way as the bodies of other men, so as to prove the reality of His human nature.
Objection: 1. It would seem that Christ's body was not animated in the first instant of its conception. For Pope Leo says (Ep ad Julian.): "Christ's flesh was not of another nature than ours: nor was the beginning of His animation different from that of other men." But the soul is not infused into other men at the first instant of their conception. Therefore neither should Christ's soul have been infused into His body in the first instant of its conception.
2. Further, the soul, like any natural form, requires determinate quantity in its matter. But in the first instant of its conception Christ's body was not of the same quantity as the bodies of other men when they are animated: otherwise, if afterwards its development had been continuous, either its birth would have occurred sooner, or at the time of birth He would have been a bigger child than others. The former alternative is contrary to what Augustine says (De Trin. iv), where he proves that Christ was in the Virgin's womb for the space of nine months: while the latter is contrary to what Pope Leo says (Serm. iv in Epiph.): "They found the child Jesus nowise differing from the generality of infants." Therefore Christ's body was not animated in the first instant of its conception.
3. Further, whenever there is "before" and "after" there must be several instants. But according to the Philosopher (De Gener. Animal. ii) in the generation of a man there must needs be "before" and "after": for he is first of all a living thing, and afterwards, an animal, and after that, a man. Therefore the animation of Christ could not be effected in the first instant of His conception.
On the contrary Damascene says (De Fide Orth. iii): "At the very instant that there was flesh, it was the flesh of the Word of God, it was flesh animated with a rational and intellectual soul."
I answer that For the conception to be attributed to the very Son of God, as we confess in the Creed, when we say, "who was conceived by the Holy Ghost," we must needs say that the body itself, in being conceived, was assumed by the Word of God. Now it has been shown above (Question , Articles ,2) that the Word of God assumed the body by means of the soul, and the soul by means of the spirit, i.e. the intellect. Wherefore in the first instant of its conception Christ's body must needs have been animated by the rational soul.
Reply to Objection: 1. The beginning of the infusion of the soul may be considered in two ways. First, in regard to the disposition of the body. And thus, the beginning of the infusion of the soul into Christ's body was the same as in other men's bodies: for just as the soul is infused into another man's body as soon as it is formed, so was it with Christ. Secondly, this beginning may be considered merely in regard to time. And thus, because Christ's body was perfectly formed in a shorter space of time, so after a shorter space of time was it animated.
2. The soul requires due quantity in the matter into which it is infused: but this quantity allows of a certain latitude because it is not fixed to a certain amount. Now the quantity that a body has when the soul is first infused into it is in proportion to the perfect quantity to which it will attain by development: that is to say, men of greater stature have greater bodies at the time of first animation. But Christ at the perfect age was of becoming and middle stature: in proportion to which was the quantity of His body at the time when other men's bodies are animated; though it was less than theirs at the first instant of His conception. Nevertheless that quantity was not too small to safeguard the nature of an animated body; since it would have sufficed for the animation of a small man's body.
3. What the Philosopher says is true in the generation of other men, because the body is successively formed and disposed for the soul: whence, first, as being imperfectly disposed, it receives an imperfect soul; and afterwards, when it is perfectly disposed, it receives a perfect soul. But Christ's body, on account of the infinite power of the agent, was perfectly disposed instantaneously. Wherefore, at once and in the first instant it received a perfect form, that is, the rational soul.
Objection: 1. It would seem that Christ's flesh was first of all conceived, and afterwards assumed. Because what is not cannot be assumed. But Christ's flesh began to exist when it was conceived. Therefore it seems that it was assumed by the Word of God after it was conceived.
2. Further, Christ's flesh was assumed by the Word of God, by means of the rational soul. But it received the rational soul at the term of the conception. Therefore it was assumed at the term of the conception. But at the term of the conception it was already conceived. Therefore it was first of all conceived and afterwards assumed.
3. Further, in everything generated, that which is imperfect precedes in time that which is perfect: which is made clear by the Philosopher (Metaph. ix). But Christ's body is something generated. Therefore it did not attain to its ultimate perfection, which consisted in the union with the Word of God, at the first instant of its conception; but, first of all, the flesh was conceived and afterwards assumed.
On the contrary Augustine says (De Fide ad Petrum xviii [*Written by Fulgentius]): "Hold steadfastly, and doubt not for a moment that Christ's flesh was not conceived in the Virgin's womb, before being assumed by the Word."
I answer that As stated above, we may say properly that "God was made man," but not that "man was made God": because God took to Himself that which belongs to man---and that which belongs to man did not pre-exist, as subsisting in itself, before being assumed by the Word. But if Christ's flesh had been conceived before being assumed by the Word, it would have had at some time an hypostasis other than that of the Word of God. And this is against the very nature of the Incarnation, which we hold to consist in this, that the Word of God was united to human nature and to all its parts in the unity of hypostasis: nor was it becoming that the Word of God should, by assuming human nature, destroy a pre-existing hypostasis of human nature or of any part thereof. It is consequently contrary to faith to assert that Christ's flesh was first of all conceived and afterwards assumed by the Word of God.
Reply to Objection: 1. If Christ's flesh had been formed or conceived, not instantaneously, but successively, one of two things would follow: either that what was assumed was not yet flesh, or that the flesh was conceived before it was assumed. But since we hold that the conception was effected instantaneously, it follows that in that flesh the beginning and the completion of its conception were in the same instant. So that, as Augustine [*Fulgentius, De Fide ad Petrum xviii] says: "We say that the very Word of God was conceived in taking flesh, and that His very flesh was conceived by the Word taking flesh."
2. From the above the reply to the Second Objection is clear. For in the same moment that this flesh began to be conceived, its conception and animation were completed.
3. The mystery of the Incarnation is not to be looked upon as an ascent, as it were, of a man already existing and mounting up to the dignity of the Union: as the heretic Photinus maintained. Rather is it to be considered as a descent, by reason of the perfect Word of God taking unto Himself the imperfection of our nature; according to Jn 6,38: "I came down from heaven."
Objection: 1. It would seem that Christ's conception was natural. For Christ is called the Son of Man by reason of His conception in the flesh. But He is a true and natural Son of Man: as also is He the true and natural Son of God. Therefore His conception was natural.
2. Further, no creature can be the cause of a miraculous effect. But Christ's conception is attributed to the Blessed Virgin, who is a mere creature: for we say that the Virgin conceived Christ. Therefore it seems that His conception was not miraculous, but natural.
3. Further, for a transformation to be natural, it is enough that the passive principle be natural, as stated above (Question , Article ). But in Christ's conception the passive principle on the part of His Mother was natural, as we have shown (Question , Article ). Therefore Christ's conception was natural.
On the contrary Dionysius says (Ep ad Caium Monach.): "Christ does in a superhuman way those things that pertain to man: this is shown in the miraculous virginal conception."
I answer that As Ambrose says (De Incarn. vi): "In this mystery thou shalt find many things that are natural, and many that are supernatural." For if we consider in this conception anything connected with the matter thereof, which was supplied by the mother, it was in all such things natural. But if we consider it on the part of the active power, thus it was entirely miraculous. And since judgment of a thing should be pronounced in respect of its form rather than of its matter: and likewise in respect of its activity rather than of its passiveness: therefore is it that Christ's conception should be described simply as miraculous and supernatural, although in a certain respect it was natural.
Reply to Objection: 1. Christ is said to be a natural Son of Man, by reason of His having a true human nature, through which He is a Son of Man, although He had it miraculously; thus, too, the blind man to whom sight has been restored sees naturally by sight miraculously received.
2. The conception is attributed to the Blessed Virgin, not as the active principle thereof, but because she supplied the matter, and because the conception took place in her womb.
3. A natural passive principle suffices for a transformation to be natural, when it is moved by its proper active principle in a natural and wonted way. But this is not so in the case in point. Therefore this conception cannot be called simply natural.
We must now consider the perfection of the child conceived: and concerning this there are four points of inquiry:
(1) Whether Christ was sanctified by grace in the first instant of His conception?
(2) Whether in that same instant He had the use of free-will?
(3) Whether in that same instant He could merit?
(4) Whether in that same instant He was a perfect comprehensor?
Objection: 1. It would seem that Christ was not sanctified in the first instant of His conception. For it is written (1Co 15,46): "That was not first which is spiritual, but that which is natural: afterwards that which is spiritual." But sanctification by grace is something spiritual. Therefore Christ received the grace of sanctification, not at the very beginning of His conception, but after a space of time.
2. Further, sanctification seems to be a cleansing from sin: according to 1Co 6,1: "And such some of you were," namely, sinners, "but you are washed, but you are sanctified." But sin was never in Christ. Therefore it was not becoming that He should be sanctified by grace.
3. Further, as by the Word of God "all things were made," so from the Word incarnate all men who are made holy receive holiness, according to He 2,11: "Both he that sanctifieth and they who are sanctified are all of one." But "the Word of God, by whom all things were made, was not Himself made"; as Augustine says (De Trin. i). Therefore Christ, by whom all are made holy, was not Himself made holy.
On the contrary It is written (Lc 1,35): "The Holy which shall be born of thee shall be called the Son of God"; and (Jn 10,36): "Whom the Father hath sanctified and sent into the world."
I answer that As stated above (Question , Articles ,10,12), the abundance of grace sanctifying Christ's soul flows from the very union of the Word, according to Jn 1,14: "We saw His glory . . . as it were of the Only-Begotten of the Father, full of grace and truth." For it has been shown above (Question , Articles ,3) that in the first instant of conception, Christ's body was both animated and assumed by the Word of God. Consequently, in the first instant of His conception, Christ had the fulness of grace sanctifying His body and His soul.
Reply to Objection: 1. The order set down by the Apostle in this passage refers to those who by advancing attain to the spiritual state. But the mystery of the Incarnation is considered as a condescension of the fulness of the Godhead into human nature rather than as the promotion of human nature, already existing, as it were, to the Godhead. Therefore in the man Christ there was perfection of spiritual life from the very beginning.
2. To be sanctified is to be made holy. Now something is made not only from its contrary, but also from that which is opposite to it, either by negation or by privation: thus white is made either from black or from not-white. We indeed from being sinners are made holy: so that our sanctification is a cleansing from sin. Whereas Christ, as man, was made holy, because He was not always thus sanctified by grace: yet He was not made holy from being a sinner, because He never sinned; but He was made holy from not-holy as man, not indeed by privation, as though He were at some time a man and not holy; but by negation---that is, when He was not man He had not human sanctity. Therefore at the same time He was made man and a holy man. For this reason the angel said (Lc 1,35): "The Holy which shall be born of thee." Which words Gregory expounds as follows (Moral. xviii): "In order to show the distinction between His holiness and ours, it is declared that He shall be born holy. For we, though we are made holy, yet are not born holy, because by the mere condition of a corruptible nature we are tied . . . But He alone is truly born holy who . . . was not conceived by the combining of carnal union."
3. The Father creates things through the Son, and the whole Trinity sanctifies men through the Man Christ, but not in the same way. For the Word of God has the same power and operation as God the Father: hence the Father does not work through the Son as an instrument, which is both mover and moved. Whereas the humanity of Christ is as the instrument of the Godhead, as stated above (Question , Article , ad 3; Question , Article , ad 1). Therefore Christ's humanity is both sanctified and sanctifier.
Objection: 1. It would seem that Christ as man had not the use of free-will in the first instant of His conception. For a thing is, before it acts or operates. Now the use of free-will is an operation. Since, therefore, Christ's soul began to exist in the first instant of His conception, as was made clear above (Question , Article ), it seems impossible that He should have the use of free-will in the first instant of His conception.
2. Further, the use of free-will consists in choice. But choice presupposes the deliberation of counsel: for the Philosopher says (Ethic. iii) that choice is "the desire of what has been previously the object of deliberation." Therefore it seems impossible that Christ should have had the use of free-will in the first instant of His conception.
3. Further, the free-will is "a faculty of the will and reason," as stated in the FP, Question , Article , Objection : consequently the use of free-will is an act of the will and the reason or intellect. But the act of the intellect presupposes an act of the senses; and this cannot exist without proper disposition of the organs---a condition which would seem impossible in the first instant of Christ's conception. Therefore it seems that Christ could not have the use of free-will at the first instant of His conception.
On the contrary Augustine says in his book on the Trinity (Gregory: Regist. ix, Ep 61): "As soon as the Word entered the womb, while retaining the reality of His Nature, He was made flesh, and a perfect man." But a perfect man has the use of free-will. Therefore Christ had the use of free-will in the first instant of His conception.
I answer that As stated above (Article ), spiritual perfection was becoming to the human nature which Christ took, which perfection He attained not by making progress, but by receiving it from the very first. Now ultimate perfection does not consist in power or habit, but in operation; wherefore it is said (De Anima ii, text. 5) that operation is a "second act." We must, therefore, say that in the first instant of His conception Christ had that operation of the soul which can be had in an instant. And such is the operation of the will and intellect, in which the use of free-will consists. For the operation of the intellect and will is sudden and instantaneous, much more, indeed, than corporeal vision; inasmuch as to understand, to will, and to feel, are not movements that may be described as "acts of an imperfect being," which attains perfection successively, but are "the acts of an already perfect being," as is said, De Anima iii, text. 28. We must therefore say that Christ had the use of free-will in the first instant of His conception.
Reply to Objection: 1. Existence precedes action by nature, but not in time; but at the same time the agent has perfect existence, and begins to act unless it is hindered. Thus fire, as soon as it is generated, begins to give heat and light. The action of heating, however, is not terminated in an instant, but continues for a time; whereas the action of giving light is perfected in an instant. And such an operation is the use of free-will, as stated above.
2. As soon as counsel or deliberation is ended, there may be choice. But those who need the deliberation of counsel, as soon as this comes to an end are certain of what ought to be chosen: and consequently they choose at once. From this it is clear that the deliberation of counsel does not of necessity precede choice save for the purpose of inquiring into what is uncertain. But Christ, in the first instant of His conception, had the fulness of sanctifying grace, and in like manner the fulness of known truth; according to Jn 1,14: "Full of grace and truth." Wherefore, as being possessed of certainty about all things, He could choose at once in an instant.
3. Christ's intellect, in regard to His infused knowledge, could understand without turning to phantasms, as stated above (Question , Article ). Consequently His intellect and will could act without any action of the senses.Nevertheless it was possible for Him, in the first instant of His conception, to have an operation of the senses: especially as to the sense of touch, which the infant can exercise in the womb even before it has received the rational soul, as is said, De Gener. Animal. ii, 3,4. Wherefore, since Christ had the rational soul in the first instant of His conception, through His body being already fashioned and endowed with sensible organs, much more was it possible for Him to exercise the sense of touch in that same instant.
Objection: 1. It would seem that Christ could not merit in the first instant of His conception. For the free-will bears the same relation to merit as to demerit. But the devil could not sin in the first instant of his creation, as was shown in the FP, Question , Article . Therefore neither could Christ's soul merit in the first instant of its creation---that is, in the first instant of Christ's conception.
2. Further, that which man has in the first instant of his conception seems to be natural to him: for it is in this that his natural generation is terminated. But we do not merit by what is natural to us, as is clear from what has been said in the FS, Question , Article ; FS, Question , Article . Therefore it seems that the use of free-will, which Christ as man had in the first instant of His conception, was not meritorious.
3. Further, that which a man has once merited he makes, in a way, his own: consequently it seems that he cannot merit the same thing again: for no one merits what is already his. If, therefore, Christ merited in the first instant of His conception, it follows that afterwards He merited nothing. But this is evidently untrue. Therefore Christ did not merit in the first instant of His conception.
On the contrary Augustine [*Paterius, Expos. Vet. et Nov. Test. super Ex 40, says: "Increase of merit was absolutely impossible to the soul of Christ." But increase of merit would have been possible had He not merited in the first instant of His conception. Therefore Christ merited in the first instant of His conception.
I answer that As stated above (Article ), Christ was sanctified by grace in the first instant of His conception. Now, sanctification is twofold: that of adults who are sanctified in consideration of their own act; and that of infants who are sanctified in consideration of, not their own act of faith, but that of their parents or of the Church. The former sanctification is more perfect than the latter: just as act is more perfect than habit; and "that which is by itself, than that which is by another" [*Aristotle, Phys. viii]. Since, therefore, the sanctification of Christ was most perfect, because He was so sanctified that He might sanctify others; consequently He was sanctified by reason of His own movement of the free-will towards God. Which movement, indeed, of the free-will is meritorious. Consequently, Christ did merit in the first instant of His conception.
Reply to Objection: 1. Free-will does not bear the same relation to good as to evil: for to good it is related of itself, and naturally; whereas to evil it is related as to a defect, and beside nature. Now, as the Philosopher says (De Coelo ii, text. 18): "That which is beside nature is subsequent to that which is according to nature; because that which is beside nature is an exception to nature." Therefore the free-will of a creature can be moved to good meritoriously in the first instant of its creation, but not to evil sinfully; provided, however, its nature be unimpaired.
2. That which man has at the first moment of his creation, in the ordinary course of nature, is natural to him. but nothing hinders a creature from receiving from God a gift of grace at the very beginning of its creation. In this way did Christ's soul in the first instant of its creation receive grace by which it could merit. And for this reason is that grace, by way of a certain likeness, said to be natural to this Man, as explained by Augustine (Enchiridion xl).
3. Nothing prevents the same thing belonging to someone from several causes. And thus it is that Christ was able by subsequent actions and sufferings to merit the glory of immortality, which He also merited in the first instant of His conception: not, indeed, so that it became thereby more due to Him than before, but so that it was due to Him from more causes than before.
Summa Th. III EN Qu.32 a.4