Therefore, just as circumcision began from Abraham, and the Sabbath and sacrifices and offerings and feasts from Moses—and it has been shown that these were ordained on account of the hardness of heart of your people—so likewise they had to cease, according to the will of the Father, in Him who was to be born the Son of God, the Christ, through the virgin from the race of Abraham and the tribe of Judah and of David; who also was proclaimed as about to come as an eternal law and a new covenant for the whole world, as the prophecies quoted above signify.
And we who have drawn near to God through Him have not received this circumcision according to the flesh, but a spiritual one, which Enoch and those like him kept. And we received it through baptism, since we had become sinners, by the mercy that comes from God; and it is granted to all alike to receive it in the same way.
Now, since the matter of the mystery of His birth presses to be spoken of, I will speak. Isaiah, therefore, concerning the origin of Christ, that it is indescribable to men, spoke thus, as has also been written above: "Who shall declare His generation? For His life is taken away from the earth; because of the iniquities of my people He was led to death." Since, then, this generation of Him who was about to die—that by His stripes we sinful men might be healed—was indescribable, the prophetic Spirit said these things.
Furthermore, in order that the men who believe in Him might recognize in what manner He came to be born in the world, the prophetic Spirit prophesied through the same Isaiah, foretelling how it was to come about, thus:
"And the Lord spoke again to Ahaz, saying: Ask for yourself a sign from the Lord your God, in the depth or in the height. And Ahaz said: I will not ask, nor will I tempt the Lord. And Isaiah said: Hear then, O house of David. Is it a small thing for you to weary men? And how do you weary the Lord? Therefore the Lord Himself will give you a sign: Behold, the virgin shall conceive and bear a son, and His name shall be called Emmanuel. Butter and honey shall He eat."
"Before the child knows or chooses the evil, He shall choose the good; for before the child knows good or evil, He refuses the evil to choose the good. For before the child knows how to call father or mother, He shall take the power of Damascus and the spoils of Samaria before the king of the Assyrians. And the land shall be forsaken, which you will hardly bear from before the two kings. But God shall bring upon you and upon your people and upon your father's house days which have not yet come upon you, from the day when Ephraim took away from Judah the king of the Assyrians."
That, therefore, in the race of Abraham according to the flesh no one has ever been born of a virgin, nor is recorded as having been so born, except this our Christ—this is manifest to all.
But since you and your teachers dare to say that it is not even stated in the prophecy of Isaiah, "Behold, the virgin shall conceive," but "Behold, the young woman shall conceive and bear a son," and since you interpret the prophecy as referring to Hezekiah, who became your king, I will attempt in this matter too to argue briefly against you and to demonstrate that it was spoken concerning Him whom we confess to be the Christ.