We should carefully note the order of the words here, and the more firmly they are engrafted in our heart, the more evident it will be that the sum total of our redemption consists in them. For they proclaim with perfect clarity that the Lord Jesus, that is, our Savior, was both the true Son of God the Father and the true Son of a mother who was a human being. “Behold,” he says, “you will conceive in your womb and give birth to a son”—acknowledge that this true human being assumed the true substance of flesh from the flesh of the Virgin! “He will be great and will be called the Son of the Most High”—confess too that this same Son is true God of true God, co-eternal Son forever of the eternal Father!
Venerable Bede, Homilies on the Gospels
And hear again how Isaiah in express words foretold that He should be born of a virgin; for he spoke thus: “Behold, a virgin shall conceive, and bring forth a son, and they shall say for His name, ‘God with us.’” For things which were incredible and seemed impossible with men, these God predicted by the Spirit of prophecy as about to come to pass, in order that, when they came to pass, there might be no unbelief, but faith, because of their prediction. But lest some, not understanding the prophecy now cited, should charge us with the very things we have been laying to the charge of the poets who say that Jupiter went in to women through lust, let us try to explain the words. This, then, “Behold, a virgin shall conceive,” signifies that a virgin should conceive without intercourse. For if she had had intercourse with any one whatever, she was no longer a virgin; but the power of God having come upon the virgin, overshadowed her, and caused her while yet a virgin to conceive. And the angel of God who was sent to the same virgin at that time brought her good news, saying, “Behold, you shall conceive of the Holy Ghost, and shall bear a Son, and He shall be called the Son of the Highest, and you shall call His name Jesus; for He shall save His people from their sins,”—as they who have recorded all that concerns our Savior Jesus Christ have taught, whom we believed, since by Isaiah also, whom we have now adduced, the Spirit of prophecy declared that He should be born as we intimated before. It is wrong, therefore, to understand the Spirit and the power of God as anything else than the Word, who is also the firstborn of God, as the prophet Moses declared; and it was this which, when it came upon the virgin and overshadowed her, caused her to conceive, not by intercourse, but by power. And the name Jesus in the Hebrew language means Σωτήρ (Savior) in the Greek tongue. Therefore, too, the angel said to the virgin, “You shall call His name Jesus, for He shall save His people from their sins.”
Justin Martyr, First Apology XXXIII
