The doctrine of the virgin birth does not so much show us Mary’s absence of a relationship to a man—although it does do that. This doctrine centrally points to her Son’s relationship to God. Jesus was born the normal way, but He was not conceived the normal way. This tells us something of His identity as the holy Son of the Most High God.
“Therefore the Lord himself shall give you a sign; Behold, a virgin shall conceive, and bear a son, and shall call his name Immanuel” (Is. 7:14).
Summary of the Text:
The text before us has a double meaning. King Ahaz, despite his resistance to it, was being given a word of reassurance by the prophet Isaiah. He was worried about an alliance between the Syrians and the northern kingdom of Israel. Isaiah tries to reassure him, and tells him that he can ask for any sign he pleases (vv. 10-11). Ahaz refuses to do so in a display of faux humility (v. 12), and so Isaiah gives him a unilateral, unasked-for sign.
The rising power of Assyria was a real problem. In 738, the king Tiglath-pileser started to move against Syria and Israel. Judah wanted to stay out of it, and so Syria and Israel tried to depose Ahaz in order to force Judah to join their coalition. That is what Ahaz was worried about. The sign being given to Ahaz was not the sign of a remarkable conception, but rather the sign of a remarkable fall of the nations he was so worried about, within a very short time frame. A woman would conceive, but before her child had grown to the age of ethical discretion, knowing to refuse evil and choose the good, the kings that Ahaz was so worried about would both be gone. Before that child got to the age of being able to eat solid food, this northern challenge to Ahaz would be removed. The woman is unnamed, but she was clearly known to both Isaiah and Ahaz—it could have been one of their respective wives, or some other woman known to them.