"The good of the grace of one soul is greater than the good of the nature of the whole universe"
- St Thomas Aquinas Ia IIa, q.24, a. 3, ad 2

— A Commentary on the Third Part of St Thomas' Theological Summa

by Reginald Garrigou-Lagrange, O. P.


After the consideration of the hypostatic union in itself, we must now discuss the nature of this union on the part of the person assuming.

John of St. Thomas observes in the beginning of his commentary on this third question that St. Thomas divides it into two parts: 1. the person assuming (a. 1-5); 2. the manner of the assumption (a. 6-8).

First Article: Whether It Is Fitting For A Divine Person To Assume

Cajetan says the purport of this title is to show that the question of this article concerns the divine person as such, so far as we introduce a mental distinction between person and the divine nature.[659]

State of the question. It is apparent from the first two difficulties presented at the beginning of the article, namely, that there is no possibility of any addition to a divine person because this person is in Himself infinitely perfect. Also incommunicability belongs to the concept of person.

Conclusion. To assume a nature is most properly befitting to a person.

Authoritative proof. St. Augustine, who is quoting St. Fulgentius, says: "This God, that is, the Only-begotten One, took the form, that is, the nature of a servant to His own person."

Proof from reason. It may be expressed in syllogistic form as follows: The word "assume," which practically means to take to oneself, is both the principle and the term of an act. But only a person can be both the principle and term of an act. Therefore only a person can assume.

The other articles of this question will bring out more clearly the meaning of the adverb "most properly."

Proof of minor. It belongs to a person to act, for actions are attributed to supposita, and a person is that which by itself separately exists and acts. Moreover a person is the term of this assumption, because the union took place in the person and not in the nature.

Assumption is properly an action by which the human nature is drawn into the subsistence of the Son, so that it may subsist by this subsistence. Hence this action not only produces in the human nature of Christ a relation of dependence on the Word, but communicates to it the personality of the Word.

Reply to first objection. No addition is made to the divine person, who is infinite. But what is divine is united to man. Hence not God, but man is perfected.

Reply to second objection. "A divine person is said to be incommunicable inasmuch as it cannot be predicated of several supposita, but nothing prevents several things being predicated of the person.... But this is proper to a divine person, on account of its infinity, that there should be a concourse of natures in it, in subsistence."[660]

Doubt. Does the termination of another nature belong exclusively to a divine person, so that it would be repugnant to every created or creatable personality? Can an angel, for example, or a devil assume the human nature? Some thought that St. John the Baptist was an angel incarnate, and that Antichrist will be a devil incarnate.

Reply. It is the common teaching among theologians that no created person can assume a nature into union with its suppositum. So say Cajetan, Soto, Alvarez, Medina, Suarez, Vasquez, Billuart. The reason is that finite personality derives its limitation and species from the nature whose complement and term it is. Although subsistence is the mode and term of the nature, it does not specify the nature, but is specified by it. Thus we speak of the human personality, or of the angelic personality; hence it implies a contradiction for the same personality of one nature to terminate another. On the contrary, the divine personality because of its infinity, as St. Thomas says,[661] is above both genus and species and contains formally and eminently the power of all possible personalities.

Second Article: Whether It Is Befitting To The Divine Nature To Assume

State of the question. The meaning of the title is, as Cajetan remarks, whether de facto it is true that the Deity, or rather God, assumed the human nature.[662]

It seems not to be true, because the union did not take place in the nature, but in the person; also because to assume in this manner could be said of the three persons.

Nevertheless, St. Augustine or rather St. Fulgentius, who is quoted in the counter-argument, says that the divine nature took our nature.

Conclusion. In the strictest sense a person is said to assume inasmuch as it is both principle and term of the assumption. In a secondary sense, however, it can be said that the Deity or God assumed the human nature inasmuch as the Deity was the principle of the assumptive act but not its term. The whole article must be read.[663]

All the other articles of this question, on the supposition of the real possibility, even of the very fact of the incarnation of the Word, examine what else was either possible or impossible. I say: "on the supposition of the real possibility of the incarnation of the Word," which, as already stated, is neither demonstrated by reason alone, nor can be disproved, but is persuaded and defended against those denying it, and is firmly held by faith.

Third Article: Whether The Nature Abstracted From The Personality Can Assume

State of the question. The meaning of the title is: Can the divine nature assume a nature different from its own, if by God we understand, in the way the pagans and Jews imagine Him to exist, without personal relations and without persons, as our Catholic faith acknowledges to be in Him?

It seems that the divine nature cannot so assume; because, as stated above, it befits the nature to assume because of the person, and because the union took place not in the nature, but in the person.

Reply. It is affirmed, nevertheless, that the divine nature can assume our nature.

Proof. It is taken from the counterargument of this article, from the argumentative part and from the reply to the second objection. The reasons given are: 1. In this hypothesis, God's omnipotence, by which the Incarnation took place, would remain. 2. There would also remain the one personality of God as the Jews understand, which could be the term of the assumption.[664]

In God, the Deity and God are identical, or in God whereby it is and what is are the same; for God's essence is His self-existing being.[665]

First doubt. Is it something absolute or something relative that immediately terminates the human nature of Christ?

Reply. It is something relative that immediately and proximately terminates Christ's human nature, namely, the personality of the Word, which is constituted by relative subsistence, or by the subsisting relation of sonship, as explained in the treatise on the Trinity. The divine relations are subsisting relations, inasmuch as their inexistence (esse in) is substantial and not accidental as in created predicamental relations, for example, in created paternity and created sonship.[666]

Proof. The Eleventh Council of Toledo in its profession of faith says: "Neither the Holy Spirit nor God the Father, but only the person of the Son took flesh."[667] But if the Word were to terminate the human nature formally and proximately by a common and absolute subsistence, then the Father and the Holy Spirit equally with the Son, would have been incarnate.

Second doubt. Could the triune God assume the human nature primarily on account of absolute subsistence, and only secondarily on account of relative subsistences?

Reply. The triune God could have assumed absolutely our human nature, because this absolute subsistence "could be the principle and term of this assumption," as stated by St. Thomas in this article.[668] For the reason why God subsists in His own nature, can be the reason why He subsists in a different nature. But absolute and common subsistence could be the reason for His subsistence in a different nature.

Third doubt. What is the difference between the incommunicability of absolute subsistence and of relative subsistence?

Reply. The first incommunicability is not within the Trinity, but only external to it. The second incommunicability is both internal and external to the Trinity. Common and absolute subsistence does not formally attribute incommunicability internally to the Deity, for the Deity is communicated to the Son and to the Holy Ghost. On the contrary, the personality of the Father is not communicated to the Son. But God by reason of His common and absolute subsistence is incommunicable externally, in this sense that He is by Himself separately existing, really and essentially distinct from the world. St. Thomas says: "A person is said to be incommunicable inasmuch as it cannot be predicated of several supposita."[669]

What the philosopher means by saying that God is personal, is that He is the separately existing being, distinct from every creature, intelligent and free and so is externally incommunicable. When theologians speak of the three divine persons, what they first of all have in mind is internal incommunicability. Thus the Father communicates the whole divine nature to the Son, but not His personality, which is the subsistent relation of paternity in opposition to filiation.[670]

Objection. The Fathers and councils never mention this absolute subsistence, which seems to have been discovered by Cajetan.

Reply. They never referred to it because there was no occasion of doing so to refute errors against it such as Nestorianism and Monophysitism, which had not yet arisen. It sufficed to exclude union in the nature and affirm the union in the person of the Word, as recorded in revelation. Absolute subsistence was not discovered by Cajetan, for St. Thomas explicitly refers to it in this third article.

Fourth Article: Whether One Person Without Another Can Assume A Created Nature

State of the question. The difficulty, as presented by the first objection, is that assumption, being a certain external operation, pertains to all three persons, who operate externally by a common omnipotence. Thus it has been shown[671] that the Trinity of persons cannot be known from creatures by natural reason; for "the creative power of God is common to the whole Trinity."[672]

Reply. Nevertheless it is of faith that only the Son of God became incarnate, neither the Father nor the Holy Spirit. The Eleventh Council of Toledo says: "We believe that of these three persons, only the person of the Son... true man... assumed[our nature]."[673]

The body of the article contains the solution of the difficulty arising from the definition of assumption, or to assume.

Assumption implies two things: the act of assuming and the term of the assumption. But revelation says that only the person of the Son is the term of the assumption. Therefore assumption, considered as the term, applies only to the person of the Son, although considered as an act, it is common to the three persons.

Thus we said that the Father and the Holy Ghost united the human nature with the Word, but They did not assume it in the sense of term.

Fifth Article: Whether Each Of The Divine Persons Could Have Assumed Human Nature

State of the question. The difficulty is, as stated in the second objection, that by the divine Incarnation, men acquired the adoption of sons, which is a participated likeness of natural sonship, which applies only to the Son. Therefore it seems that only the Son could be incarnate. Moreover, to be incarnate is to be sent, which cannot apply to the Father, who cannot be sent by any person, since the other two persons proceed from Him.

Reply. Nevertheless it is affirmed, that each of the persons could have assumed human nature. For to assume another nature is befitting to God because of His omnipotence, as the principle of the assumption, and because of His person, as the term of the assumption. But each of the divine persons is omnipotent and has His own personality. Therefore each of the divine persons could have assumed human nature.

Reply to first objection. It was fitting, if the Father became incarnate, for Him as man to have been the Son of man, for example, the son of David; for this would be according to difference of natures, and would not result in confusion of realities, but at most of names.

Reply to second objection. It contains a beautiful scriptural text concerning adoptive sonship, which is a certain participated likeness of natural sonship. But if the Father became incarnate, we would have received this adoptive sonship from Him, as coming from the principle of natural sonship;[674] but farther on in this question, it is shown that it was more fitting for the Son to have become incarnate.[675]

Reply to third objection. The Father, who is innascible as to eternal birth, could have been born temporally as man if He had become incarnate. In such case the Incarnation would not have been a mission. Thus the Father dwells in the just, as the Son and the Holy Ghost do, but He is not sent, and so He comes without being sent; whereas the other two persons are sent by Him. So the pope sends His legate, but he himself is not sent, but comes.

Sixth Article: Whether Several Divine Persons Can Assume One And The Same Individual Nature

State of the question. The meaning is: Can the three persons assume this human nature, terminating it proximately and immediately by their own relations?

The difficulty is that it could not then be said the human nature is assumed by one man or by several men, because there would be one human nature and three divine persons who possess it.

Reply. Yet St. Thomas affirms the possibility of the three persons assuming one and the same human nature. It is the commonly accepted teaching, but it was attacked by Scotus.

Indirect proof. It is taken from the counterargument of this article, and proceeds by way of analogy; for just as the divine nature is common to the three persons, so likewise the human individualized nature can be common to Them.

A more direct and proper proof is found in the argumentative part of this article. It may be expressed by the following syllogism.

The divine persons do not exclude one another from communicating in the same nature, since they terminate together the same divine nature.

But in the mystery of the Incarnation, the whole reason of the deed is the power of the doer, as Augustine says.

Therefore in passing judgment on the act, we must take into special consideration the condition of the person assuming, who does not exclude the other two persons from communicating in the same nature.

There is no repugnance on the part of the human nature, because it can be assumed, not by reason of its natural limited power, but because of its obediential power, which extends to all that is not essentially repugnant.

What is truly impossible is for a divine person to assume a human person, for then there would be two persons in one person.

Reply to first objection. It contains the solution of the difficulty proposed in the objection, namely, that, granting the hypothesis, it would be true to say that the three divine persons were one man, because of the one human nature, just as we say that they are one God, because of the one divine nature, which is one numerically, without any multiplication and division.[676]

Seventh Article: Whether One Divine Person Can Assume Two Human Natures

State of the question. This question is posited, as the preceding questions are, so as to make it known more clearly in what the mystery of the Incarnation consists on the part of the person assuming.

The difficulty is that there would be one suppositum for two natures of the same species, for example, the same divine person would be Peter and John. Another difficulty is that it could not then be said that the person incarnate is one man, because He would have two human natures; nor several men, because several men have distinct supposita. It is not apparent how these two human natures could be united to each other, one of these natures being perhaps in one part of the world, and the other in another part.

Reply. St. Thomas affirms, however, the possibility of such an assumption.

Indirect proof. It is taken from the counter-argument of this article, and may be expressed by the following syllogism.

Whatever the Father can do externally, the Son also can do. But after the Incarnation, the Father can assume a human nature distinct from that assumed by the Son. Therefore the Son can assume a human nature distinct from the one He assumed.

Direct proof. This same principle is again invoked, as in the following syllogism.

The power of a divine person, both as regards the principle in the assumption and as regards the term of the assumption, is infinite; nor can it be restricted to what has been created. But a divine person would be restricted in power if He could assume only one human nature. Therefore a divine person can assume more than one human nature.

Some have objected that such two human natures would interpenetrate.

Reply. To establish the truth of this conclusion, it is not necessary for the divine person to assume these two natures in the same place; for divine immensity makes it possible for any of the divine persons to assume one of the human natures in Rome, and the other in some place far away from this city. Such action involves no absurdity.[677]

Reply to first objection. "There can be a numerical multitude on the part of the nature, on account of the division of matter, without distinction of supposita."

Reply to second objection. There would still be one man, and not several, because there is only one suppositum. In fact, one divine person could assume many individual human natures, and there would be no pantheism in this for there would be no confusion of the divine nature with the human nature; but all these natures would be impeccable. Toletus gave us a good rule to follow, one that is taken from the teaching of St. Thomas. He says: "For the multiplication of concrete substantive names both kinds of multitude are required, namely, of supposita and of forms; the absence of one results in unity."[678]

Eighth Article: Whether It Was More Fitting That The Person Of The Son Rather Than Any Other Divine Person Should Assume Human Nature

State of the question. It seems that it is not, because the effect of the Incarnation is a kind of second creation, which befits the Father, inasmuch as creative power is appropriated to Him. Besides, the Incarnation is ordained to the remission of sins, which is attributed to the Holy Ghost.

Conclusion. Yet it was most fitting that the person of the Son should become incarnate, and this for three reasons.

1) Because of the principle of the union. All things were made by the Word, as by the exemplary cause. Therefore it was fitting that ail things be restored by the Word. Thus the craftsman, by the intelligible form or concept of his art, whereby he fashioned his handiwork, restores it when it has fallen into ruin.

2) The end of the union. It was fitting that He who is the natural Son of God, should make us adoptive sons.[679] He received by eternal generation the whole divine nature without its being multiplied or divided; but we receive a participation of the divine nature, or the radical principle of strictly divine operations, and finally a participation of the beatific vision.[680]

3) Reparation for sin. An inordinate desire for knowledge had resulted in the sin and spiritual death of man. Hence it was fitting that reparation be made by Him to whom wisdom is attributed.

St. Paul says: "[God] predestinated[us] to be made conformable to the image of His Son, that He might be the first-born among many brethren."[681] St. Thomas in commenting on this text[682] shows clearly that adoptive sonship is a participated likeness of natural and eternal sonship. Adoption is generally known as the legal acceptance of an unrelated person as son.[683] To adopt is to admit someone freely as heir to one's estate.[684] It befits the whole Trinity to adopt men, "although in God, to beget belongs to the person of the Father, yet to produce any effect in creatures is common to the whole Trinity, by reason of the oneness of Their nature; because, where there is one nature, there must be one power and one operation."[685] The adopted son of God is not strictly begotten, but made; yet sometimes it may be said that he is begotten, by reason of spiritual regeneration, which is gratuitous and not natural. Hence it befits the whole Trinity to adopt men as sons.

Nevertheless St. Thomas says: "Adoptive sonship is a certain likeness of the eternal sonship.... Now man is likened to the splendor of the eternal Son by reason of the light of grace which is attributed to the Holy Ghost. Therefore adoption, though common to the whole Trinity, is appropriated to the Father as its author; to the Son as its exemplar, to the Holy Ghost as imprinting on us the likeness of this exemplar."[686] It is easy to assign similarities and differences between the divine, natural, eternal sonship and adoptive sonship; for the Son of God is by nature begotten, not made; He is light of light, true God of true God; possesses the whole Deity that can neither be divided nor multiplied. The adopted son is made, not begotten, but he is spiritually born of God by grace, which is a participation of the divine nature, and this radically disposes him for strictly divine acts, namely, to see God face to face and love Him for all eternity.

Recapitulation. What has been discussed in this third question will enable us to acquire a better understanding of the hypostatic union in all its aspects so far considered.

Therefore it has been established that in the strictest sense it befits a divine person to assume a created nature, that is, take it to Himself (a. 1 and 2). Nevertheless, God as conceived by Jews and Monotheists, not consisting of three persons who are related to one another, could assume a created nature, because He is omnipotent, and He could terminate this nature by absolute subsistence, which is common to the three divine persons.

It follows from this, as has been stated, that anyone of the divine persons could assume the human nature. In fact, the three divine persons could assume one and the same human nature, just as they have one and the same divine nature.

Finally, one divine person could assume two human natures, because the power of the person on the part of the principle and the term of the assumption is infinite. But although these divers hypotheses are possible, it was more fitting that the Son of God rather than the Father or the Holy Ghost should assume the human nature of Christ.

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"A man should keep himself down, and not busy himself in mirabilibus super se."

St Philip Neri

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"The Lord has always revealed to mortals the treasures of his wisdom and his spirit, but now that the face of evil bares itself more and more, so does the Lord bare his treasures more."

St John of the Cross, OCD - Doctor of the Church

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"The greatest glory we can give to God is to do his will in everything."

St Alphonsus de Liguori

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