“So the only begotten God being born man of a Virgin and in the fullness of the time, being Himself ordained to work out the advance of man to God, observed this order of things, through all the words of the gospels, that He might teach belief in Himself, as Son of God, and keep us in mind to preach Him as Son of Man. As being man He always spoke and acted as is proper to man, but in such a manner as never to speak in this same mode of speech as touching both save with the intention of signifying both God and Man. But hence the heretics derive a pretext for catching in their traps simple and ignorant men: what was spoken by our Lord in accordance with His manhood they falsely assert to have been uttered in the weakness of His divine nature, and since one and the same person spoke all the words He used they urged that all He uttered He uttered about Himself. Now even we do not deny that all His extant words are of His own nature. But granted that the one Christ is man and God; granted that when man He was not then first God; granted that when man He was then also God, granted that after the assumption of the manhood in the Lord, the Word was man and the Word was God, it follows of necessity that there is one and the same mystery of His words as there is of His generation. Whenever in Him, as occasion may require, you distinguish the manhood from the Godhead, then also endeavour to separate the words of God from the words of man. And whenever you confess God and man, then discern the words of God and man. And when the words are spoken of God and man, and again of man wholly and wholly of God, consider carefully the occasion. If anything was spoken to signify what was appropriate to a particular occasion, apply the words to the occasion. A distinction must be observed between God before the manhood, man and God, man wholly and God wholly after the union of the manhood and Godhead. Take heed therefore not to confuse the mystery of the incarnation in the words and acts. For it must needs be that according to the quality of the kinds of natures a distinction lies in the manner of speech, before the manhood was born, in accordance with the mystery when it was still approaching death, and again when it was everlasting. 'For if in His birth and in His passion and in His death He acted in accordance with our nature He nevertheless effected all this by the power of His own nature.'”
Of the same in the same book:—
“Do you then see that thus God and man are confessed, so that death is predicated of man, and the resurrection of the flesh, of God; for consider the nature of God and the power of the resurrection, and recognise in the death the œconomy as touching man. And since both death and resurrection have been brought about in their own natures, bear in mind, I beg you, the one Christ Jesus, who was of both. I have shortly demonstrated these points to you to the end that we may remember both natures to have been in our Lord Jesus Christ 'for being in the form of God He took the form of a servant.'”
Testimony of the very holy bishop Augustinus.
From his letter to Volusianus. Epistle III:
“But now He appeared as Mediator between God and man, so as in the unity of His person to conjoin both natures, by combining the wonted with the unwonted, and the unwonted with the wonted.”
Of the same from his exposition of the Gospel according to John: —
“What then, O heretic? Since Christ is also man, He speaks as man; and do you slander God? He in Himself lifts man's nature on high, and you have the hardihood to cheapen His divine nature.”
Of the same from his book on the Exposition at the Faith:—
“It is ours to believe, but His to know, and so let God the Word Himself, after receiving all that is proper to man, be man, and let man after His assumption and reception of all that is God, be no other than God. It must not be supposed because He is said to have been incarnate and mixed that therefore His substance was diminished. God knows that He mixes Himself without the natural corruption, and He is mixed in reality. He knows also that He so received in Himself as that no addition of increment accrues to Himself, as also He knows He infused His whole self so as to incur no diminution. Let us not then, in accordance with our weak intelligence, and forming conjectures on the teaching of experience and the senses, suppose that God and man are mixed after the manner of things created and equal mixed together, and that from such a confusion as this of the Word and of the flesh a body as it were was made. God forbid that this should be our belief, lest we should suppose that after the manner of things which are confounded together two natures were brought into one hypostasis. For a mention of this kind implies destruction of both parts; but Christ Himself, containing but not contained, who examines us but is Himself beyond examination, making full but not made full, everywhere at one and the same time being Himself whole and pervading the universe, through His pouring out His own power, as being moved with mercy, was mingled with the nature of man, though the nature of man was not mingled with the divine.”
Testimony of Severianus, bishop of Gabala.
From “the Nativity of Christ”:—
“O mystery truly heavenly and yet on earth— mystery seen and not apparent for so was the Christ after His birth; heavenly and yet on earth; holding and not held; seen and invisible; of Heaven as touching the nature of the Godhead, on earth as touching the nature of the manhood; seen in the flesh, invisible in the spirit; held as to the body not to be holden as to the Word.”
Testimony of Atticus, bishop of Constantinople.
From his letter to Eupsychius:—
“How then did it behoove the Most Wise to act? By mediation of the flesh assumed, and by union of God the Word with man born of Mary, He is made of either nature, so that the Christ made one of both, as constituted in Godhead, abides in the proper dignity of His impassible nature, but in flesh, being brought near to death, at one and the same time shows the kindred nature of the flesh how through death to despise death, and by His death confirms the righteousness of the new covenant.”
Testimony of Cyril, bishop of Alexandria.
From his letter to Nestorius: —
“The natures which have been brought together in the true unity are distinct, and of both there is one God and Son, but the difference of the natures has not been removed in consequence of the union.”
Of the same from his letter against the Orientals: —
“There is an union of two natures, wherefore we acknowledge one Christ, one Son, one Lord. In accordance with this perception of the unconfounded union we acknowledge the Holy Virgin as Mother of God because the Word of God was made flesh and was made man, and from the very conception united to Himself the temper taken from her.”
Of the same:—
“There is one Lord Jesus Christ, even if the difference be recognised of the natures of which we assert the ineffable union to have been made.”
Of the same:—
“Therefore, as I said, while praising the manner of the incarnation, we see that two natures came together in inseparable union without confusion and without division, for the flesh is flesh and no kind of Godhead, although it was made flesh of God; in like manner the Word is God, and not flesh, although He made the flesh His own according to the œconomy.”
Of the same from his interpretation of the Epistle to the Hebrews:—
“For although the natures which came together in unity are regarded as different and unequal with one another, I mean of flesh and of God, nevertheless the Son, Who was made of both, is one.”
Of the same from his interpretation of the same Epistle:—
“Yet though the only begotten Word of God is said to be united in hypostasis to flesh, we deny there was any confusion of the natures with one another, and declare each to remain what it is.”
Of the same from his commentaries:—
Source: Dialogues ("Eranistes" or "Polymorphus") (New Advent)