1Cor. 15:20-28 (key: 27, 28)
27 For [God] “subjected all things under his feet.” But when he says that ‘all things have been subjected,’ it is evident that it is with the exception of the one who subjected all things to him. 28 But when all things will have been subjected to him, then the Son himself will also subject himself to the One who subjected all things to him, that God may be all things to everyone.
Reasoning: This is long after Jesus' resurrection, long after Armageddon. Mankind is finally brought to perfection, Satan is eliminated. If Jesus were God, why would he "subject himself" to God? It certainly doesn't make sense that he would subject himself to himself. That is nonsense.