THESIS I: Hitherto the prior part of the incarnation. The other follows, which is the joining of the two natures, divine and human, made in that conception: which is called the personal union, and is defined as the joining of these two nature, the divine and the human, in Christ, whereby the person of the Son of God took to Himself a human nature, and in this way united it to His divine nature, so that the one person of Christ, consisting in two natures, is both God and man at the same time, or the θεάνθρωπος/Theanthropos/God-man, for the purpose of uniting God and man in covenant.
EXPLANATION: * There is a notable passage in Bernard,[1] in his Vigilia Nativitatis Domini, Sermon 3: That omnipotent majesty performed three works, made three conjunctions, in the taking of our flesh; so singularly miraculous and miraculously singular that neither are such done, nor are to be done again, upon the earth. Indeed, there is a conjunction between God and man, Mother and Virgin, faith and the human heart. Those unions are astounding, and more marvelous than all miracles, since since such diverse and such separate things were able to be brought together.
THESIS II: The causes and effects of this union are to be considered.
THESIS III: The two distinct natures, the divine and the human are the Matter, which two are united in the person of τοῦ λόγου, the Logos, or Son of God: whence it is called personal.
EXPLANATION: I. The second person of the Deity, the λόγος/ Logos, or Son of God, took to Himself a human, not person, but nature, without its own mode of subsistence or personality, and personally united it to His divine nature, so that the one person of Christ might be furnished with two natures, the divine and the human: which Scripture indicates, when it says, that the λόγον/Logos, that is, the speech or word, was made flesh, John 1:14. That the Son of God took on Himself the seed of Abraham, Hebrews 2:16. The Matter of the hypostatic union is either the two natures, the divine and the human, or the human nature and the second person of the Trinity, whence this union is distinguished into immediate and mediate.
The immediate is between the person of τοῦ λόγου, the Logos, and the human nature, which the λόγος/Logos assumed into the unity of person.
The mediate is between the divine nature and the human nature. For, to the human nature is united the divine only in the person of τοῦ λόγου, the Logos: whence neither the Father nor the Holy Spirit was incarnated: although the divine nature of the Father and of the Holy Spirit is altogether the same as that of τοῦ λόγου, the Logos. This was also carefully marked by the Fathers, especially after the Eutychian[2] controversies: Concerning this matter Rusticus Diaconus discourses excellently, in his dialogo contra Acephalos,[3] chapter 10, page 154: Not God the Word through the divine nature, but the divine nature through the person of the Word of God, is said to be united to flesh. For, if the whole Trinity had willed to be incarnated, then perhaps that nature would have been incarnated properly through itself. For, all things that are present to that nature according to itself and because of itself are common to the Trinity, and are not proper to any one person alone. But incarnation is not common to the Trinity, but proper to the subsistence of the Word alone. Therefore, God, the Word and His nature, has been incarnated, but He indeed through Himself, and relatively: but that not in such a way, but through the person, etc.
II. Against the evident testimonies of Scripture some Photinians take exception.
(1.) That in the saying of John, by Word is not understood the Son of God, but a certain decree of God: that to be made flesh is not to take up a human nature, but to be made humble and abject.
Response: 1. John attributes to the Word or τῷ λόγῳ, the Logos, things that are only able to be attributed to the personal λόγῳ/Logos, but not to a decree of God: of which sort are, that He was with God, and was God; that He was creator of things; that He is that light which illuminate every man coming into the world; that He came to His own; that He did abide among men; that He is the only-begotten; that He was sent forth from the Father; etc. Hence that Word, which in this place is said to have been made flesh, God manifested in the flesh, 1 Timothy 3:16, is also said to be God’s Son, made of a woman, Galatians 4:4.
2. To be made flesh is not to be made humble and abject, but to be made man, with a human nature assumed; this is evident from other passages: as when God is said to have been manifest in the flesh. Likewise, the Son of God was made of a woman, in the passages previously cited. Hebrews 2:16, He is said to have taken on Himself the seed of Abraham.
(2.) To assume the seed of Abraham is nothing other than the taking of the seed of Abraham by Christ unto gracious favor.
Response: This is a false gloss: for by the assumption of the seed of Abraham the Son of God was made the brother of the children of Abraham, and like unto them in all things, sin excepted. In this seed, having suffered and been tempted, He expiated sins, verses 17, 18. Through this seed He was made a partaker of flesh and blood. But not is He made the brother of the children of Abraham, and like unto them in all things, nor a partaker of flesh and blood; nor does He suffer for the expiation of sins, who merely takes the seed of Abraham into gracious favor: Otherwise the same things could be said of God the Father, who also Himself took the seed of Abraham into gracious favor.
THESIS IV: The Form or mode of this union consists: (1.) In the perpetual and intimate conjunction of the divine and human natures. (2.) In the distinction and preservation of both natures. (3.) In the unity of the person, consisting in two natures.
EXPLANATION: I. When the mode of the personal union is said to consist in the perpetual and intimate conjunction of the divine and human natures, it is signified, that the bond of this union is indissoluble forever; and so it is never going to be the case, that the Son of God is going to put off the flesh assumed, and cease to be a man; or that the human nature is going to be separated from the person: in which sense by the Greek Churches it is said that the union was made ἀδιαιρέτως καὶ ἀχωρίστως, indivisibly and inseparably.
II. When the mode of this union is said to consist in the distinction and preservation of both natures, it is signified that, even if this union of the natures is the closest and most intimate, they are not confounded with one another, in such a way that one nature is made out of the two, nor changed, so that the one might be transformed into the other. Whence the union is said to have been made ἀσυγχύτως καὶ ἀτρέπτως, without confusion and mutation. Which is to be held against the heretic Eutyches, who formerly taught that the human and divine natures were confounded into one: and so he acknowledged only one nature in Christ. This heresy was of old condemned by the council of Chalcedon.
Now, the natures are understood to be distinct, or diverse; which are distinguished by their properties. For, if the properties be destroyed or confused, the natures themselves are destroyed or confused.
Thus the human nature of Christ is a creature, is visible, tangible, finite, with respect to essence, duration, and power, composed of body and soul, formerly liable to various passions and death: as the Evangelical history testifies. Whence he says in Hebrews 2:17, that Christ was obliged to be made like unto His brethren, that is, us, in all things.
The divine nature of Christ is God, is invisible, intangible, infinite, with respect to essence, duration, and power; free of all composition, impassible, immortal.
Therefore, the natures remain distinct, as long as they remain distinct in properties, and the properties of the one are not common to the other.
III. When the mode of this union is said to consist in the unity of the person, consisting in the two natures, it is signified, that the person of Christ is one, who nevertheless has in Himself two natures, namely, the divine and the human, whereby He is true God and true man. Whence the union is said to have been made in the two natures preserved and concurring in the one person. Which is to be held against Nestorius,[4] who two that there were two persons in Christ, the one, which is man, the other, which is God. This heresy was of old condemned at the first council of Ephesus.
That Christ is only one person, is proven:
(1.) Because He that was obliged to be born of Mary is called the Son of God, Luke 1:35. Therefore, the Son of God and the Son of Mary is one person, which was born of the Virgin Mary according to His human nature.
(2.) Because the Scripture expressly says, that we have one Mediator, 1 Timothy 2:5; one Lord, Ephesians 4:5.
But, if there be two persons in Christ, we would have two mediators and two Lords.
(3.) Because the proper and altogether diverse actions of both natures, the divine and the human, are attributed to one and the same Christ, who, as He is God and man, so is eternal and begotten in time, infinite and finite, invisible and visible, creator and creature, passible and impassible, dead and immortal, etc.
Therefore, the person of Christ is one, consisting in two natures, the properties of which He claims for Himself, with respect to the natures: so that, as Christ is eternal, according to the divine nature: the same is begotten in time, according to the human nature: He is finite, according to the human nature; infinite, according to the divine nature.
IV. The Nestorians and Photinians impugn this doctrine: the latter, from the hypothesis of another, namely, ours, concerning two distinct natures in Christ: the former, from their own hypothesis, which yet they hold in common with us, concerning the two natures.
[Therefore, the Photinians argue in this way:]
If there are two whole and complete natures in Christ, differing in their properties by their entire genus, then there are also two persons.
But the consequent is false: Therefore also the antecedent.
The rationale of the hypothetical is: Because two natures, whole and complete, and distinct, and those singular and understanding, necessarily constitute two persons.
Response: The hypothetical is not conceded, except concerning natures whole and complete, not only with respect to essence, but also with respect to peculiar and proper subsistence. But the human nature of Christ, even if it has a perfect human essence, yet it is without its own subsistence, because it was determined for the completion of the other person of the θεανθρώπου/ Theanthropos/God-man, or was assumed by another person into the unity of person. Not even in created things does the diversity of two individual natures argue a duality of persons: as it is evident from the example of the human body and soul.
The Nestorians thus argue:
Where there are distinct and perfect natures, singular and intelligent, there are also two distinct persons.
But in Christ there are two distinct natures, singular and perfect, human and divine.
Therefore, in Him are also distinct persons, the human and the divine.
They prove the major by induction. In the cases of Peter, James, and John, there are natures singular, perfect, and distinct in number, which constitute just so many persons, distinct in number. The rationale of all other individual men is the same.
Response: The major is not universally true, unless with the distinction of natures also concurs a distinction and perfection of proper subsistence, which is not in both natures of Christ. The proof is inconsequent: because the rationale with respect to the subsistence of individual natures in Peter, James, and John is one thing; but another of the natures in Christ, and in particular, of the human. The individual nature of Peter, James, and John was not designed for another person distinct from Peter or James, but is the very person of Peter and of James. But the human nature of Christ was designed for another person, namely, the person of the Son of God, to whom it is personally united, and so is not the person either of Christ or of a man personally distinct from Christ.
They insist: If from the human nature of Christ a proper subsistence does not result, and that human, it will be less perfect than the individuals of another nature; for example, of Peter, James, and John: whence emanate proper human subsistences.
But the consequent is absurd: Therefore also the antecedent.
Response: The hypothetical is denied. The proof is inconsequent: for, that a proper human subsistence does not immediately result from the human nature of Christ is not by its imperfection, but by a miracle of divine power, which prevented that emanation of a proper subsistence: because He willed the human nature of Christ to be, not a person, but the nature of the person.
THESIS V: The Efficient is the Most Holy Trinity, but with a singular relation to the Holy Spirit, by whose power was accomplished that miraculous conception; and thus the union of the human nature with the divine λόγου/ Logos is to be held in admiration: and indeed at one and the same moment; so that without the personal union with the λόγου/Logos the human nature never existed, not even according to the body or the soul.
EXPLANATION: The reason is: If Christ’s human nature or body had existed previously, and had been conceived without the person of the λόγου/ Logos, Christ, or the Son of God, could not be said to have been conceived in the womb of the Virgin: for, neither the flesh nor the human is called Christ or the Son of God in Scripture. But the Angel expressly testifies, a Virgin shall conceive the Son of the Most High. Whence also the Blessed Virgin is most properly called θεοτόκος/theotokos, the mother of God; because she brought Him forth, who is both God and man: even though she did not bring forth the Deity.
THESIS VI: The End of the personal union is the union of God and men in the covenant of grace. For, so that GOD and man might be made one in the covenant of grace, it was necessary that GOD and man be made one in person.
EXPLANATION: Scripture testifies to this, Galatians 4:4, 5, when the fulness of time was come, God sent forth His Son, made of a woman, made under the law, so that He might redeem them that were under the law, that we might receive the adoption of sons.
[1] Bernard of Clairvaux (1091-1157) was a Cistercian monk and abbot, whose learning and austere piety made him very influential in his day.
[2] Eutyches (c. 380-c. 456) was a presbyter of Constantinople. He opposed Nestorius, arguing that Christ was a mixture of human and divine elements. He was excommunicated at the Council of Chalcedon in 451.
[3] Rusticus Diaconus (flourished mid-sixth century) was a defender of Chalcedonian Christology against monophysitism.
[4] Nestorius (c. 386-451) taught that in Christ, there are not only two natures, but two persons, Jesus of Nazareth and the eternal Son of God. Some believe that this was not actually Nestorius’ view, but rather his opponents’ caricature of his beliefs.