Why did Jesus have to be God in order to die for the sins of the world?
Jesus had to be God because only the Creator of the universe could taste death for every man and pay the sin debt of every human being. As the God of Genesis 1:1, He took on flesh and went to the cross; God was in Christ, reconciling the world to Himself.
Les explains that the One who hung on the cross was the Creator of the universe, the same God of Genesis 1:1 who called everything into being. He had to be that God, or He could never have tasted death for every man or paid the sin debt of every human being. Jesus Christ is the God of creation who took on flesh and went the way of the cross. Paul writes that God was in Christ, reconciling the world back to Himself after Adam lost it, not imputing trespasses unto them.
To wit, that God was in Christ, reconciling the world unto himself, not imputing their trespasses unto them; and hath committed unto us the word of reconciliation.