When God became man: The promise of a unique birth

"Therefore the Lord Himself will give you a sign: Behold, a virgin will be with child and bear a son, and she will call His name Immanuel" (Is. 7:14).

When God became man, it was through a conception and birth like no other. Isaiah prophesies a virgin -- a woman who has no natural means of procreation -- will give birth to a son. This impossible pregnancy and birth will constitute a sign -- a sign of the most miraculous kind.

The father of this child is not mentioned in this verse. Only later is it spelled out this son has God as His Father, but we certainly can deduce this reality from Isaiah's prophecy. Only God can do something so impossible. This child will be human and divine. In this baby boy, God would fulfill His promise from long before.