 But God can also do anything he wants to do, including take on flesh and be 100% man and still not cease to be God. So he had to die in our place to pay for our sins. God couldn't die, so he takes on flesh as a man. Nor can a man endure the wrath of God, because that is what it means when he says that he poured out his wrath on his own son to die in our place. So that's why he's both God and man.