But what is the beginning of Theodore's unification of them? Theodore examines various conceivable ways of uniting the Divinity and humanity. He counts three such ways: 1) unity in essence, 2) the dwelling of God the Word κατ' ενέργειαν, 3) unity by goodwill.

But (1) the first method of uniting the natures is impossible, because the unity of κατ' ούσίαν is conceivable only where the natures to be united are of the same essence (όμοούσια). In relation to other substances, this means that God is omnipresent and is not encompassed by any place. To say that God dwells in Jesus Christ in essence is to say either too much or too little, i.e., either to say that God dwells only in Christ and nowhere else — but this is impossible, or to express the general idea that God is omnipresent, and therefore dwells in Jesus Christ — but in this sense God is inherent even in inanimate nature.

2) The second method of uniting natures, κατ' ενέργειαν, arouses the same perplexities as the first. To say that He acts in Christ is either to limit the divine action to one place, if He acts only in Christ, which is contrary to the absoluteness of God, or to equate Jesus Christ with all other things in the world in which God acts.

3) There remains a third way, dwelling by good will, the method of which is also spoken of in the Holy Scriptures. In the Scriptures: "I will dwell in them, and I will be like them" (Leviticus XXVI, 12; cf. Ps. CXLVI, 11). Here we stand on the correct dogmatic point of view, and at the same time the highest one. If God lived only in His omnipresence, then He would be bound by the necessity that lies in His being, He would dwell in both the good and the evil; but living by good pleasure, God is completely morally free. Under this category must also be thought the union of the two natures in Jesus Christ. Theodore sees that the "contact of natures" here is thought to be analogous to the indwelling of God in other holy people; he is aware that the modus of union in Christ does not differ toto genere from the form of God's indwelling in the saints; but he admits an undeniable (essentially quantitative) difference in kind. God's favor is able to diversify the form of one's presence. "We have not gone mad," says Theodore, "to think that in Christ God dwells only in the same specific sense as in the prophets. No, He dwells in Christ as in the Son."

In his epistle to Domnus, [later] Bishop. Antiochian, which constitutes a kind of compendium of his theology, he points out the important consequences of "living according to good will." This abode, this union (ενωσις) of natures, assigns to both natures one name, one will and action, authority, power, dominion, and dignity, and this union is by no means separate, for both natures constitute one person (πρόσωπον) and are called one person. The method of union essentially has an application in relation to those of one essence, but in its application to those of other essences such a method is impossible, since it would lead to their merging. Thus, according to the method of benevolence, the two natures are united from the mother's womb, have one person, both are preserved inseparably and inseparably, and reveal in everything the identity of will and action, and it is impossible to imagine anything closer than this union (ών ούδέν εστιν συναφέστερον).

{p. 154}

Thus, we see that the dogmatic language of Theodore rests on a special theoretical underpinning, which cannot be ignored. For example, it is impossible to offer him a direct demand that he recognize ενωσιν κατ' ουσίαν, when he connected with this term a completely different meaning from that which Orthodox dogmatics assimilates to him. Nor can his system be attacked on the simple etymological ground that συνάφεια does not mean unity, but an external and most superficial contact, when Theodore himself believes that his system speaks of a union so complete and close that behind it there is already direct consubstantiality or fusion.

But Theodore's theoretical assumptions were undoubtedly erroneous. Comparing the Incarnation with the grace of the prophets, he omitted the obvious difference that in the prophets God dwells in essence, i.e. the Father, the Son and the Holy Spirit. The Spirit (a fact that for the ancient theologian was obscured, it is true, by the then widespread θεολογούμενον that the God of revelation is, almost exclusively, God the Word), and in Christ not all of the Holy Spirit was incarnated. Trinity, but only God the Word; so that the resemblance in this analogy is very small, and the difference (toto genere) is quite substantial.

Having brought to the fore the inseparability and non-merging of the two natures, Theodore spent all the means of theological vocabulary to clarify this point. First, φύσις in his system had a meaning equivalent to ύπόστασις, so that δύο φύσεις = δύο υποστάσεις. Secondly, although this difference of natures is brought to unity by the fact that they constituted one person, εν πρόσωπον, yet the strength of this unity is weakened by other explanations of Theodore.

a) He did not bother to explain this unity by referring to Matt. XIX, 6, where it is said of husband and wife: "To this there are two, but the flesh is one." "Just as in this case the actual duality does not prevent their unity, so when we distinguish the natures, we speak of the perfect nature of God the Word and of the perfect person: for it is impossible to speak of an impersonal hypostasis (άπρόσωπον); in the same way we speak of the perfect nature of man and of the perfect person. But when we consider natures from the point of view of their contact, we speak of one person. One person now embraces two natures, and humanity accepts the honor given to creation to the Divinity, and the Divinity fulfills all that is due in human beings." Consequently, Theodore is on the side of the view that a non-hypostatic nature is impossible, and for the hypostatic nature he constantly demands the idea of a person. It is clear that the main thing for Theodore of Mopsuestia is duality, and not unity.

b) Recognizing the right to consider human nature as a special person, Theodore could comfortably present Christ's earthly life as human and follow the relationship of Jesus to God the Word. For the history of Christ's earthly life, Theodore takes an unmistakably Arian point of view: "God from eternity foresaw the highly moral life of Jesus, and in view of this He chose Him as the organ and temple of His Divinity." Jesus Christ was born in a supernatural way, and from the very moment of His conception God the Word began to dwell in Him. Nevertheless, in the early stages of earthly life, the "contact" between God the Word and Jesus was relatively incomplete.

In humanity, during adolescence, Christ gave the impression of a child of genius; Christ amazed with His knowledge, His intellect and moral development. He also had a natural opportunity for this, being a man pure from sin by virtue of a supernatural birth; but in addition to this, God the Word, who dwelt in Him, contributed to His progress. The life of Jesus had the character of constant moral improvement; before the distinction between good and evil is noticed in ordinary children, He discovered a striving exclusively for good.

Before baptism, Jesus Christ lived as one under the law; He perfectly fulfilled the law and thus justified Himself through the law. When the time came, He appeared for baptism, which was for Him a spiritual rebirth: He also became the Son of God according to humanity. From this time begins the second period of His life, life under grace. He is morally absolutely perfect, not because He is not subject to temptation, but because He heroically endures temptation. In proportion as He is perfected, His path to higher perfection becomes easier and easier, and He manifests in Himself the ideal of the moral life: the συνάφεια with the Logos is realized more and more completely.

Finally, after death on the cross, comes the third stage of His existence, the period of glorification, deification. However, Theodore finds an analogy for this deification: in the future life we will be guided by the spirit both in soul and body. Thus, Christ appears as the greatest ascetic, and His "unity" or "contact" with God the Word increased in proportion to His real moral perfection.