Cyril of Alexandria"I have been amazed that some are utterly in doubt as to whether or not the holy Virgin is able to be called the Mother of God. For if our Lord Jesus Christ is God, how should the holy Virgin who bore him not be the Mother of God?" (Letter to the Monks of Egypt 1 [A.D. 427]). "This expression, however, ‘the Word was made flesh’ [John 1:14], can mean nothing else but that he partook of flesh and blood like to us; he made our body his own, and came forth man from a woman, not casting off his existence as God, or his generation of God the Father, but even in taking to himself flesh remaining what he was. This the declaration of the correct faith proclaims everywhere. This was the sentiment of the holy Fathers; therefore they ventured to call the holy Virgin ‘the Mother of God,’ not as if the nature of the Word or his divinity had its beginning from the holy Virgin, but because of her was born that holy body with a rational soul, to which the Word, being personally united, is said to be born according to the flesh" (First Letter to Nestorius [A.D. 430]). "And since the holy Virgin corporeally brought forth God made one with flesh according to nature, for this reason we also call her Mother of God, not as if the nature of the Word had the beginning of its existence from the flesh" (Third Letter to Nestorius [A.D. 430]).
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