Proof that the Virgin Mother of God was not only Christotocos but also Theotocos, and that Christ is truly God.
And so you say, O heretic, whoever you may be, who deny that God was born of the Virgin, that Mary the Mother of our Lord Jesus Christ ought not to be called Theotocos, i.e., Mother of God, but Christotocos, i.e., only the Mother of Christ, not of God. 2389 For no one, you say, brings forth what is anterior in time. And of this utterly foolish argument whereby you think that the birth of God can be understood by carnal minds, and fancy that the mystery of His Majesty can be accounted for by human reasoning, we will, if God permits, say something later on. 2390 In the meanwhile we will now prove by Divine testimonies that Christ is God, and that Mary is the Mother of God. Hear then how the angel of God speaks to the Shepherds of the birth of God. “There is born,” he says, “to you this day in the city of David a Saviour who is Christ the Lord.” 2391 In order that you may not take Christ for a mere man, he adds the name of Lord and Saviour, on purpose that you may have no doubt that He whom you acknowledge as Saviour is God, and that (as the office of saving belongs only to Divine power) you may not question that He is of Divine power, in whom you have learnt that the power to save resides. But perhaps this is not enough to convince your unbelief, as the angel of the Lord termed Him Lord and Saviour rather than God or the Son of God, as you certainly most wickedly deny Him to be God, whom you acknowledge to be Saviour. Hear then what the archangel Gabriel announces to the Virgin Mary. “The Holy Ghost,” he says, “shall come upon thee, and the power of the Most High shall overshadow thee: therefore also that holy thing which shall be born of thee shall be called the Son of God.” 2392 Do you see how, when he is going to point out the nativity of God, he first speaks of a work of Divinity. For “the Holy Ghost,” he says, “shall come upon thee, and the power of the Most High shall overshadow thee.” Admirably did the angel speak, and explain the majesty of the Divine work by the Divine character of his words. For the Holy Ghost sanctified the Virgins womb, and breathed into it by the power of His Divinity, and thus imparted and communicated Himself to human nature; and made His own what was before foreign to Him, taking it to Himself by His own power and majesty. 2393 And lest the weakness of human nature should not be able to bear the entrance of Divinity the power of the Most High strengthened the ever to be honoured Virgin, so that it supported her bodily weakness by embracing it with overshadowing protection, and human weakness was not insufficient for the consummation of the ineffable mystery of the holy conception, since it was supported by the Divine overshadowing. “Therefore,” he says, “the Holy Ghost shall come upon thee, and the power of the Most High shall overshadow thee.” If only a mere man was to be born of a pure virgin why should there be such careful mention of the Divine Advent? Why such intervention of Divinity itself? Certainly if only a man was to be born from man, and flesh from flesh, a command alone might have done it, or the Divine will. For if the will of God alone, and His command p. 557 sufficed to fashion the heavens, form the earth, create the sea, thrones, and seats, and angels, and archangels, and principalities, and powers, and in a word to create all the armies of heaven, and those countless thousands of thousands of the Divine hosts (“For He spake and they were made, He commanded and they were created” 2394 ), why was it that that was insufficient for the creation of (according to you) a single man, which was sufficient for the production of all things divine, and that the power and majesty of God did not entrust that with the birth of a single infant, which had availed to fashion all things earthly and heavenly? But certainly the reason why all those works were performed by the command of God, but the nativity was only accomplished by His coming was because God could not be conceived by man unless He allowed it, nor be born unless He Himself entered in; and therefore the archangel pointed out that the sacred majesty would come upon the Virgin, I mean that as so great an event could not be brought about by human appointment, he announced that there would be present at the conception the glory of Him who was to be born. 2395 And so the Word, the Son, descended: the majesty of the Holy Ghost was present: the power of the Father was overshadowing; that in the mystery of the holy conception the whole Trinity might cooperate. “Therefore,” he says, “also that holy thing which shall be born of thee shall be called the Son of God.” Admirably does he add “Therefore,” in order to show that this would therefore follow because that had gone before; and that because God had come upon her at the conception therefore God would be present at the birth. And when the maiden understood not, he gave a reason for this great thing, saying: “Because the Holy Spirit shall come upon thee, and because the power of the Most High shall overshadow thee, therefore also that holy thing which shall be born shall be called the Son of God;” that is to say: That thou mayest not be ignorant of the provision for so great a work, and the mystery of this great secret, the majesty of God shall therefore come upon thee completely; because the Son of God shall be born of thee. What further doubt can there be about this? or what is there further to be said? He said that God would come upon her; that the Son of God would be born. Ask now, if you like, how the Son of God can help being God, or how she who brought forth God can fail to be Theotocos, i.e., the Mother of God? This alone ought to be enough for you; aye this ought to be amply sufficient for you.
The Nestorian controversy was originated by a sermon of Anastasius, a follower of Theodore of Mopsuestia, whom Nestorius brought with him to Constantinople as his chaplain on his appointment as Archbishop, a.d. 428. This man, preaching in the presence of the archbishop, said: “Let no one call Mary Theotocos; for Mary was but a woman, and it is impossible that God should be born of a woman.” In the controversy which was immediately excited by these words Nestorius at once took the part of his chaplain and preached a course of sermons in maintenance of his views; refusing to the Blessed Virgin the title of Theotocos, while admitting that she might be termed Christotocos. See Socrates H. E. Book VII.. c. xxxii., Evagrius H. E. Book I. c. ii., and Vincentius Lirinensis Book I. c. xvii. The sermons are still partially existing in the writings of Marius Mercator: and in the second of them the title Χριστοτόκος is admitted. Cf. Hefeles Councils Book IX. c. i. (Vol. iii. Eng. Transl. p. 12 sq.).556:2390
The subject is dealt with in Book IV. c. ii.; VII. c. ii. sq.556:2391
S. Luke ii. 11.556:2392
S. Luke i. 35.556:2393
On the conception by the Holy Ghost compare Pearson on the Creed. Article III. c. ii.557:2394
Petschenigs text is as follows: Videlicet ut, quia agi tanta res per humanum officium non valebat, ipsius ad futuram diceret majestatem in conceptu, qui erat futurus in partu; while Gazæus reads deceret for diceret.