Letter 104: I have already informed your holiness in another letter how openly my accusers are slandering my teaching.

To Flavianus, Bishop of Constantinople, I have already informed your holiness in another letter how openly my accusers are slandering my teaching. Now I do the same through these most devout bishops, who serve as witnesses to my orthodoxy -- along with the countless others who have heard me preach in the churches of the East. Beyond all these, I have my conscience, and the One who sees my conscience. I know that the divine apostle often appealed to the testimony of his conscience: "Our boasting is this: the testimony of our conscience" [2 Corinthians 1:12], and again, "I speak the truth in Christ, I do not lie, my conscience bearing me witness in the Holy Spirit" [Romans 9:1]. Know then, holy and revered sir, that no one has ever at any time heard me preach two sons. That doctrine seems to me abominable and impious. For "there is one Lord Jesus Christ, through whom are all things" [1 Corinthians 8:6]. Him I acknowledge as both eternal God and man in the last days, and I give him one worship as Only-Begotten. I have, however, learned to distinguish between flesh and Godhead, for the union is unconfused [a key Antiochene Christological term: the two natures are united but not blended into each other]. Thus, drawn up in battle formation against the madness of Arius and Eunomius, we easily refute their blasphemy against the Only-Begotten: we apply what was spoken in humility about the Lord -- what belongs fittingly to his assumed nature -- to the man, and what is appropriate to the divine nature and signifies divinity, to God. We do not divide him into two persons. We teach that both sets of attributes belong to the Only-Begotten: the divine because he is God, Creator, and Lord of all; the human because he was made man for our sake. For divine Scripture says that he was made man not by change of the Godhead but by assumption of the manhood...

Letter 104