Part 5572

: * Further, the word "God" is predicated in common of Father, Son, and Holy Ghost. If, therefore, the Blessed Virgin is Mother of God it seems to follow that she was the Mother of Father, Son, and Holy Ghost, which cannot be allowed. Therefore the Blessed Virgin should not be called Mother of God.

* On the contrary, * In the chapters of Cyril, approved in the Council of Ephesus (P. 1, Cap. xxvi), we read: "If anyone confess not that the Emmanuel is truly God, and that for this reason the Holy Virgin is the Mother of God, since she begot of her flesh the Word of God made flesh, let him be anathema."

* I answer that, * As stated above (Q[16], A[1]), every word that signifies a nature in the concrete can stand for any hypostasis of that nature. Now, since the union of the Incarnation took place in the hypostasis, as above stated (Q[2], A[3]), it is manifest that this word "God" can stand for the hypostasis, having a human and a Divine nature. Therefore whatever belongs to the Divine and to the human nature can be attributed to that Person: both when a word is employed to stand for it, signifying the Divine Nature, and when a word is used signifying the human nature. Now, conception and birth are attributed to the person and hypostasis in respect of that nature in which it is conceived and born. Since, therefore, the human nature was taken by the Divine Person in the very beginning of the conception, as stated above (Q[33], A[3]), it follows that it can be truly said that God was conceived and born of the Virgin. Now from this is a woman called a man's mother, that she conceived him and gave birth to him. Therefore the Blessed Virgin is truly called the Mother of God. For the only way in which it could be denied that the Blessed Virgin is the Mother of God would be either if the humanity were first subject to conception and birth, before this man were the Son of God, as P