It has been said, then, that the nature of the Word became flesh, that is, was united to flesh: but that the nature of the Word suffered in the flesh we have never heard up till now, though we have been taught that Christ suffered in the flesh. So that “the nature of the Word” does not mean “the subsistence.” It remains, therefore, to say that to become flesh is to be united with the flesh, while the Word having become flesh means that the very subsistence of the Word became without change the subsistence of the flesh. It has also been said that God became man, and man God. For the Word which is God became without alteration man. But that the Godhead became man, or became flesh, or put on the nature of man, this we have never heard. This, indeed, we have learned, that the Godhead was united to humanity in one of its subsistences, and it has been stated that God took on a different form or essence ὁ Θεὸς μορφοῦται, ἤτοι οὐσιουται τὸ ἀλλότριον. Gregory of Nazianzum in his Carmen used the term οὐσιοῦσθαι of the word after the assumption of our nature. See also Dionys., De div. nom., ch. 2; Ep. ad Carmen, 4; &c., to wit our own. For the name God is applicable to each of the subsistences, but we cannot use the term Godhead in reference to subsistence. For we are never told that the Godhead is the Father alone, or the Son alone, or the Holy Spirit alone. For “Godhead” implies “nature,” while “Father” implies subsistence, just as “Humanity” implies nature, and “Peter” subsistence. But “God” indicates the common element of the nature, and is applicable derivatively to each of the subsistences, just as “man” is. For He Who has divine nature is God, and he who has human nature is man.