Chapter 5 — Part I: The Creed — Article III: Who Was Conceived by the Holy Ghost, Born of the Virgin Mary
Section 11. Hence, at the same instant He was perfect God and perfect man, and the most Holy Virgin, having at the same moment conceived God and man, is truly and properly called Mother of God and man. This the Angel signified to her when he said: Behold thou shalt conceive in thy womb, and shalt bring forth a son; and thou shalt call his name Jesus. He shall be great, and shall be called the Son of the Most High. The event verified the prophecy of Isaias: Behold a virgin shall conceive, and bear a son. Elizabeth also declared the same truth when" being filled with the Holy Ghost, she understood the Conception of the Son of God, and said: Whence is this to me, that the mother of my Lord should come to me?