The Council of Ephesus (431)
The First Anathema: Mother of God
If anyone does not confess that Emmanuel is true God, and that the holy Virgin is therefore the Mother of God, since in the flesh she bore the Word of God made flesh, as it is written, “The Word became flesh”: let him be anathema.
Nestorius’s first counter-anathema: If anyone says that Emmanuel is true God, and not rather God with us, that is, that he has united himself to a nature like ours, which he took from the Virgin Mary, and dwelt in it; and if anyone calls Mary the mother of God the Word, and not rather the mother of him who is Emmanuel; and if he maintains that God the Word changed himself into the flesh, which he took on only in order to make his Godhead visible and to be found in form as a man: let him be anathema.
Petavius: From On the Incarnation, Book 6, chapter 17. In this anathema certain words are found in the Greek copy of Dionysius that are missing from the ordinary copies, namely, “as it is written, ‘And the Word became flesh’”; unless, indeed, Dionysius supplied them on his own authority. For at the Lateran synod in the time of Martin the First, this anathema was quoted without the added words.
This anathema shatters the chief strength of the Nestorian impiety. For it sets out two facts: the first, that Emmanuel, that is, he who was born of a woman and dwelt with us, is God; the second, that Mary, who bore such a one, is Mother of God. That Christ is God is clearly proved from the Nicene Creed, and he shows that the same one who was the Son of God in the beginning afterward took flesh and was born of Mary, without any change or confusion of natures. Saint Cyril explains that by the word sarkikōs, “in a fleshly way,” he meant nothing other than kata sarka, “according to the flesh.” And this expression had to be used to overthrow the false faith of Nestorius, so that we may understand that the most holy Virgin was the parent not of a simple, bare man, but of God the Word: not in that he was God, but in that he had taken flesh. For God the Father was the parent of the same Son divinely, as his mother was after the flesh. And the word in no way lessens the dignity of his being begotten and born; for it shows that his flesh was not pretended or shadowy, but real and like ours. Amphilochius plainly uses the word, saying, “Had he not been born in the flesh, you would never have been born in the spirit.” Compare Saint Gregory of Nazianzus, Oration 51. Theodoret wrongly took Saint Cyril to teach in this first anathema that the Word was changed into the flesh he took on. But Cyril rightly treated this whole accusation as a foolish slander.