The Treatises of Cyprian

9. That this should be the sign of His nativity, that He should be born of a virgin—man and God—a son of man and a Son of God.

In Isaiah: “And the Lord went on to speak to Ahaz, saying, Ask thee a sign from the Lord thy God, in the height above and in the depth below. And Ahaz said, I will not ask, and I will not tempt the Lord my God. And He said, Hear ye, therefore, O house of David: it is no trifling contest unto you with men, since God supplies the struggle. On this account God Himself will give you a sign. Behold, a virgin shall conceive, and shall bear a son, and ye shall call His name Emmanuel. Butter and honey shall He eat; before that He knows to prefer the evil, He shall exchange the good.” This seed God had foretold would proceed from the woman that should trample on the head of the devil. In Genesis: “Then God said unto the serpent, Because thou hast done this, cursed art thou from every kind of the beasts of the earth. Upon thy breast and thy belly shalt thou crawl, and earth shall be thy food all the days of thy life. And I will place enmity between thee and the woman and her seed. He shall regard thy head, and thou shalt watch his heel.”