The three readings today are in need of some context, especially the Matthew and Isaiah passage.
Isaiah (read through chapter 7) challenges King Ahaz to chose a sign to prove that God is with them and that they have nothing to fear from the enemy. He refuses. If Ahaz chooses a sign and it did come about then the king and the people would have to obediently follow the Lord and put away their false worship. He and the people are not willing to do that so he declines the opportunity to be comforted. In other words he believes that “ignorance is bliss.”
Not to be outsmarted by a snotty nosed king, God gives him a sign anyway.
NOW the term, “virgin” used in this context (7:14) does not mean that the baby would be born as a result of a virgin birth. The word simply refers to a young maiden.
The Isaiah passage has a fulfillment in the time that it is spoken as an immediate fulfillment.
FAST FORWARD to Jesus birth. It is obvious that Matthew believes that Jesus was born to a virgin. (Matthew 1:18-19). His quotation from Isaiah 7:14 is used as an ultimate fulfillment of that prophecy, that one has come to provide ultimate comfort. Again the challenge is trumpeted to obediently follow the Lord and put away our false worship.
Jesus was completely his father’s son “full of grace and truth”
What signs has the Lord given to you that Jesus is the one who has come to comfort you?