This is a follow on from the question Why does the Messiah have to be God?

Fully Man: I agree that Jesus had to become man, I believe this is VERY well supported in the bible. Hebrews 2:17-18, Hebrews 4:14-15 and much more.

Fully God? I know that Jesus himself claimed deity, (See all the references here: Moody Global Ministries).

Question: What is the Biblical basis for saying that Jesus must be fully God and fully man? Why does Jesus have to be God himself?

Is it not sufficient that he is the son of God? The son of God can still save, the son of God can still be our intercessor, the son of God can still have fully God attributes (because he is the only son of God), the son of God can still exist from before there was time. So back to the question, WHY does Jesus have to be God?