Tomorrow I will say something regarding the claim of the First Gospel that Jesus was born of a virgin. Today, I want to mention an insight to which I have never given attention as relates to the use of Is. 7.14 in Mt. 1.23. In the context of both books that primary reason for the “sign” of these births was to guarantee the doom wicked kings!
In Is. 7.1 we discover that Ahaz is king of Judah. Rezin the king of Aram and Pekah the king of Israel go to Jerusalem to wage war against Ahaz. Isaiah is told to go to Ahaz to console him by informing him that God will not allow Aram and Israel to devastate Judah. The prophet, as the mouth of YHWH, tells Ahaz to ask for a sign so that Ahaz will know the promise of YHWH is secure. Ahaz fears testing God, so he won’t ask. YHWH chooses a sign instead.
The sign, according to Is. 7.14-16 is that a young woman ( MT: הָעַלְמָ֗ה or LXX: παρθένος, a virgin) will soon give birth to a child. This child’s birth guarantees that these kings will be judged “before the child will know enough the refuse evil and choose good” (v. 16). Matthew picks up on this.
In Mt. 1.23 he quotes this passage. In 2.1 we are introduced to Herod’s desire to kill the baby king. In 2.13 Joseph is told in a dream that he must take his wife and her child to Egypt. By 2.19 everything is resolved with Herod because Herod has died and Jesus is still a boy. Nevertheless, Joseph goes to Galilee because he doesn’t trust the new king, Archelaus.
Is the virgin birth important in and of itself for Matthew? Sure, but it is a sign to a great parallel. The parallel is not merely that Ahaz would see a young woman give birth to a son and the LXX rendering led Matthew to see Jesus’ virgin birth as necessitating something like a virgin birth. Rather, Matthew saw Jesus’ virgin birth as a sign that Herod would be disposed before the boy was mature just like Ahaz would see the evil kings disposed before the boy was born.
I will note that the one conversation that I had with someone who has read the Book of Isaiah frequently felt that this may be accurate, but he felt it to be a bit of a stretch. Do you think it makes sense or do you think I am trying too hard to find a broader connection?
the archives near Emmaus 
Behold a young woman shall conceive and bear a son and shall call his name..Immanu-el. ….Before you accuse me of fudging the verse by replacing virgin with young woman I assure..you that I pulled this out of the most accurate translation of the Bible that there is the Revised Standard..Version. That this is the correct word used here can be seen from comparing how the word translated as.. young woman is translated in other places…..The Hebrew word is ALMAH al-mah and it is used 7 times in the Bible. Strictly speaking it..means young woman but depending on the Bible that you are using it is translated as virgin maiden and..damsel as well.