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.

c) On the question of how complete was the personal unity of God and man in Christ, the paraphrase on John is important. V, 30: "I can do nothing about Myself. As I hear, I judge: My judgment is also righteous: for I seek not My will, but the will of Him who sent Me the Father," It is inconceivable for us that Jesus Christ in His self-consciousness distinguished Himself, as "I," from the Logos. Theodore of Mopsuestia admits this. He paraphrases the words of Jesus Christ as follows: "I, Whom you see, can do nothing as a man by my own nature, but I do, for the Father dwells in Me; But God the Word, the only-begotten of God, is in Me, and consequently the Father dwells with Him in Me." Thus, in Christ, His human "I" could oppose itself to the Divine "I" of the Word, and, consequently, the unity of the person did not even include the unity of self-consciousness. It is not surprising, then, if Theodore distinguishes between God the Word and Jesus as "saving" and "being saved," as "beneficent" and "beneficent."

Theodore's answer to one particular question is important for history: St. Virgin Mary Θεοτόκος or άνθρωποτόκος? — She is both (άμφότερα): She is the Mother of Man — by the nature of the fact (τη φύσει τού πράγματος), since he who was in the womb of Mary was a man; She is the Mother of God, since God was in the man born of Her.

Excursus: Origenistic disputes at the end of the ΙV and the beginning of the V century.

Theodore of Mopsuestia expressed the peculiarities of his view on the Christological question more fully than Nestorius. Next, it would be natural to proceed to an exposition of the teaching of Nestorius and the history of his work. But the history of Nestorius is not only dogmatic, but it also touched upon canonical questions. Therefore a certain intermezzo is necessary, important not in essence (in the sense of clarifying the dogmatic doctrine which was the subject of the dispute), but in order to clarify the character of the persons who took part in this dispute (in so far as the question of the sees was touched upon). In view of this, it is necessary to mention the Origenistic disputes that preceded the Nestorian dispute.

There are three stages in the Origenistic controversies of this time: Palestinian, Alexandrian, and Constantinople.

1) Jerome, who broke off his moral ties with the Roman clergy, settled near Jerusalem in the Bethlehem monastery in 386. Rufinus of Aquileia was also in Jerusalem. Their alliance with John of Jerusalem was close: they were also connected by scientific aspirations, expressed in the study of the works of Origen. Jerome understood Origen's very misfortunes and misfortunes as a consequence of malice and envy of Origen, and therefore spoke of him with praise. He proudly pointed out that he used the works of Origen: hexaples and tetrapls.

Everything seemed to promise a lasting peace. But in 393, pilgrims arrived from the west to Jerusalem, led by Aterbius. They were the prototypes of what the Spanish inquisitors later represented. Aterbius was a man who did not like to talk about things for a long time; he began with conclusions, then expressed judgments (premises), and finally – already concepts – about which they reasoned. He was dissatisfied with the fact that Western people were engaged in the study of Origen, whom he had heard of as a heretic, and demanded that Origen's errors be condemned. Jerome, sensitive to his reputation as a strictly Orthodox man, compromised his respect for Origen, condemned him; Rufinus shut himself up in his house and did not see Atherbius again, so he did not renounce Origen and remained Orthodox. This circumstance alone produced a certain bifurcation. Jerome began to behave as if he had never had any respect for Origen. Rufinus, on the other hand, still belonged to the memory of Origen.