"Matthew relates the virgin conception to the Messiah being called “God with us,” that is, deity (cf. Matthew 18:20, 28:20).
It is foundational to the Christian faith that the Son of God was born of a woman to redeem us from our sin.
(But when the fulness of the time was come, God sent forth his Son, made of a woman, made under the law, To redeem them that were under the law, that we might receive the adoption of sons. Galatians 4:4–5).
If we do not have the virgin conception,
we deny the deity of Jesus
and lose the truth of his redeeming death on the cross.
The good news of Christmas is not simply about a baby being born, but about the eternal Son of God taking on humanity to save us from our sins (Matthew 1:21)." AIG