Notes on the Union of the Two Natures in Christ

 

Different Types of Union in Aristotle and St. Cyril

Harry Wolfson identified three different types of union within Aristotelian metaphysics:

[1]. A union between two things which are not reciprocally active and passive. In this type of union, the two constituent elements remained unchanged, their union being, as it were, a "clump" or aggregate of two things. An example would the wheat and barley is what spoken of as a mixture of the two. Aristotle used the term synthesis to refer to this type of union. 

[2]. A union between reciprocally active and reciprocally passive bodies which are divisible. In such a union, each of the constituents changes out of its own nature towards the other, yet neither becomes the other. The product of such a thing is a tertium quid, a new (third) thing formed out of the constituents. 

[3]. A union between reciprocally active and passive bodies, which are divisible, but are of unequal power of action and passion. The resultant union is not a tertium quid, but rather one of the constituents, namely the one which is of greater power of action.

We also should note the other types of union listed by the scholastics (Bernard, in particular):

[1]. A conjugal unity which takes place in marriage, when the husband and wife are no longer two, but one flesh (Gen. 2:24). 

[2]. The native union whereby the soul and body make up the human person. 

Ultimately, we label the union between the two natures as a "hypostatic union", because the Logos assumed human nature into His hypostasis, so that the two natures subsisted in the one person of Christ, while remaining distinct from one another according their respective properties. Yet must not divide Christ, as the Nestorians do, by saying that the human nature of Christ has a hypostasis in and of itself which is separate from the hypostasis of the Logos. Rather, both the divine and the human subsist in the one person of the Word. 

At the end of the day, this union is ineffable and incomprehensible, and beyond human understanding. We are content only with the teaching of Scripture on this subject, and the teaching of the historic church which explicates the biblical faith concerning the person of Christ.

"When therefore we say that the Word of God was united to our nature, the mode of union is clearly above man's understanding; for it is not like one of those mentioned, but wholly ineffable and known to no one of those who are, save only to God Who knoweth all things" (St. Cyril of Alexandria, Scholia on the Incarnation, § 8)

The union of the two natures in Christ is not a natural union (as that between the soul and the body, though it has been rightly used as an analogy in explaining the hypostatic union, it is not the same and comparable in every respect), for the following reasons:

1st, things that are united naturally are such that neither is complete without the other. However, the Logos was a complete person before the incarnation. 

2nd, things that are united naturally are such that there are some third thing from them, a tertium quid. However, Christ is not ετέρων ετερον, a different thing from different things. 

The union of the two natures in Christ is not an essential union either, because this would mean that the two natures combine or are the same in essence, which is the heresy of the Monophysites. 

"For there is no predicable form of Christlihood, so to speak, that He possesses. And therefore we hold that there has been a union of two perfect natures, one divine and one human; not with disorder or confusion, or intermixture , or commingling, as is said by the God-accursed Dioscorus and by Eutyches and Severus, and all that impious company: and not in a personal or relative manner, or as a matter of dignity or agreement in will, or equality in honour, or identity in name, or good pleasure, as Nestorius, hated of God, said, and Diodorus and Theodorus of Mopsuestia, and their diabolical tribe: but by synthesis; that is, in subsistence, without change or confusion or alteration or difference or separation, and we confess that in two perfect natures there is but one subsistence of the Son of God incarnate ; holding that there is one and the same subsistence belonging to His divinity and His humanity, and granting that the two natures are preserved in Him after the union, but we do not hold that each is separate and by itself, but that they are united to each other in one compound subsistence. For we look upon the union as essential, that is, as true and not imaginary. We say that it is essential , moreover, not in the sense of two natures resulting in one compound nature, but in the sense of a true union of them in one compound subsistence of the Son of God, and we hold that their essential difference is preserved. For the created remains created, and the uncreated, uncreated: the mortal remains mortal; the immortal, immortal: the circumscribed, circumscribed: the uncircumscribed, uncircumscribed: the visible, visible: the invisible, invisible." (John of Damascus, Exposition on the Orthodox Faith, Book III, Chapter 3)

The Efficient Cause of the Union

"The efficient cause of the incarnation is, in diverse respects, both the entire Holy Trinity and the Son alone, or the Second Person of the Trinity." (Johann Gerhard, Theological Commonplaces - On Christ, pg. 95)

When it comes to speaking of the efficient cause of the incarnation, we may speak of it in two ways, either (1) inchoatively, with regard to its effecting and beginning, or (2) terminatively, with regard to the formal relationship and termination. 

With regard to the beginning and effecting of the work of the incarnation, it is attributed to the entire Trinity. But when it comes to the termination of the incarnation, it is to be attributed to the Son alone. 

"that created thing which the Virgin conceived and brought forth though it was united only to the person of the Son, was made by the whole Trinity (for the works of the Trinity are not separable)" (Augustine, Enchiridion, chapter 38)

"The work of incarnation is said to be proper to the entire Trinity as far as the act is concerned but to the Son alone as far as the terminus is concerned, the assumed flesh that belongs to the hypostasis of the Word. It is called an essential and external work [opus ad extra], or common to the entire Trinity, as far as the acting or production is concerned; it is called a personal or internal work [opus ad intra], or proper to the Son, as far as its termination or relation is concerned." (Johann Gerhard)

Question: Why did the Son, rather than the Father or the Holy Spirit, become incarnate, taking on human flesh?

Answer: For the following reasons:

[1]. "The Father could not be incarnated, for as he was the first in order he could not be sent by anyone or act as mediator to the Son and the Holy Spirit. Nor was it fitting that he, who was the Father in divine things, should become the Son in human things by being born of a virgin. The Holy Spirit could not, who was to be sent by the Mediator to the church (John 16:7), and yet he could not be sent by himself. Thus there would have been two sons, the second person by eternal generation and the third by an incarnation in time." (Francis Turretin, Institutes of Elenctic Theology, 2:305)

[2]. The Son, who was between the Father and the Holy Spirit, should be Mediator between God and man.

[3]. It was proper that He who was Son by nature (eternal generation) should make us adoptive sons by grace.

[4]. Through the Son, all things were created in the beginning (John 1:3), therefore it is fitting that the Son should also perform the work of recreating and restoring what had been corrupted through sin. Athanasius says "The Son was sent that the re-creating might be the work of Him to whom belonged the creating. For that reason we are called ‘new creatures’ in Christ (Gal. 6:15)." (Epistle to Epictetus)

Question: In Luke 1:35, the angel says to the blessed virgin Mary "The Holy Ghost shall come upon thee, and the power of the Highest shall overshadow thee." The Greek term for "overshadowing" is episkiasmos. What is meant by this?

Answer: It is to be confessed that the entirety of this work of the Holy Spirit is indescribable and incomprehensible, yet we may say the following things about it. It included the work of protection and and gracious presence of Christ, lest Mary be consumed by the divine majesty, just as God covered Moses (Exodus 33:22) when He passed by him whilst he was in the cleft of the rock. 

Some of the ancients, such as Rufinus and John Damascene, refer this work to the Son, who took up the flesh into the unity of His person. 

"So, then, after the holy Virgin assented, she was overshadowed by God Most High’s wisdom and power subsisting in His own hypostasis [enhypostatos], the Son of God, consubstantial with the Father, as the divine seed; and from her chaste and very pure blood He constructed flesh endowed with a soul." (John of Damascus, Exposition of the Orthodox Faith, Book III, Chapter 2)

This is also a plausible interpretation, since the Son is referred to in Scripture as the "power of God" (1 Cor. 1:24). 

Rules of Predication when Speaking of Christ

- The properties of one nature cannot be predicated of the other nature, neither by abstractive names or concretive names, when the other nature is signified in abstractive names. For example, it would be wrong for us to say "Christ's human nature is divine" or that "Christ's divinity is human". 

- In Scripture, there are places when the acts and properties of one nature are attributed to the person, denominated by the other nature (Acts 20:28; 1 Cor. 2:8). We can in a sense say "God died", not that the deity suffered (for it is impassible), but that the person who is God is also man. To deny this, would be to fall into Nestorianism.