Yesterday, I said this about the Incarnation:
At the incarnation we see God become man. Jesus Christ, the second person of the trinity, took upon himself human flesh. In doing so, he didn’t cease to be fully God nor did he become something more than man (either a demi-God or a super-human). Jesus became the God-Man; fully human and yet fully God with two separate natures united in one person.
I didn’t spend any time showing where such beliefs come from in the scriptures. I am simply assuming here that you know the scriptures teach these things. What I am more interested in doing here is thinking about why it matters. Yesterday, we considered why Jesus had to be fully human so, today, we will think about why it was necessary for him to be fully God.
To bear the weight of sin
If Jesus was merely human, even if he somehow managed to live a perfect human life as a second Adam, though he might be classed a sinless, spotless representative, he would not be able to bear the full weight of sin. As a mere man, Jesus would only be able to pay for sin in the same way as any other human being; namely, finitely. That represents something of a problem when we are faced with the infinite offence of sin against an infinitely holy God.
For sin to be paid for in full, it had to be paid for in a person with an infinite nature. That is to say, only God himself could take upon himself the full weight of sin and have any hope of being able to say, ‘it is finished!’ For full satisfaction, for the penalty of sin to be paid in full, required an infinite nature. If God himself did not take the punishment of sin upon himself, the price could not be paid and our sin would remain unatoned for.
To be a suitable mediator
1 Tim 2:5 tells us ‘there is one mediator between God and man, the man Christ Jesus.’ Yesterday, we saw how Hebrews demanded a human mediator who is just like us so they could adequately represent us. But that cuts both ways! Whilst we need a mediator acceptable to us, God needs a mediator acceptable to him. Someone who is just like him. The problem is, God says himself in Isaiah 45:5, ‘I am the Lord, and there is no other; there is no God but me.’ So, the only person who can represent God must, of necessity, be God. It similarly needs someone who can stand before God, acceptable to him, in order to advocate on our behalf (cf. 1 John 2:1). Unless Jesus is God, he can neither advocate for us to God nor can he mediate for God to us.
To reveal God
Jesus says, ‘anyone who has seen me has seen the Father’ (John 14:9). Jesus is the one who makes God known. But just as Paul elsewhere insists that only a person themselves can make themselves known to another (cf. 1 Cor 2:11) – though in this case he is arguing the Spirit has revealed God to the Apostles – Jesus has to be fully God in order to reveal the Father. Paul’s essential point is that we cannot know God without God making himself known to us. If Jesus is not fully God, he cannot fully or meaningfully reveal God to us. If it takes one to know one, then it takes God to reveal God. If Jesus is not fully God, he is unable to fully reveal God to us. But that is precisely what he claims to do.
To not diminish God’s glory
In Isaiah 42:8, the Lord declares: ‘I am the LORD. That is my name, and I will not give my glory to another or my praise to idols.’ In Psalm 3:8, and repeated in Revelation 7:10, we’re told, ‘Salvation belongs to the Lord’. God will not share his glory with anyone else and salvation is entirely his and belongs to no other. God simply will not let anyone else be involved in the work of salvation lest his glory be diminished and it go to some creature or other.
Of course, Jesus is pretty clearly involved – indeed, central – to the work of salvation. If he is a mere man, there’s quite a lot of glory in the work of salvation that rightly belongs somewhere other than with God alone. Yet, scripture is clear throughout, God will save his people himself. God will work salvation and he will get all the glory for it. If Jesus is only a man, we have a created being stealing the glory that rightly and properly belongs only to God. But if Jesus is fully God, and the Bible says he is, then God is the one who works salvation and all glory remains firmly with him.
This doctrine is so important. It should come as no surprise that every group that has denied the deity of Christ has ended up creating a religion that requires us to play our part in salvation and offers no meaningful hope of salvation. If Jesus is less than fully God he has necessarily less than paid for all sin and if he has failed to pay for sin there is either no hope for us or everything rests on our making up his deficit (which is just another way of saying there is no hope). if he is not fully God, we have no mediator with God who can advocate for us when we sin. The Christian faith is destroyed if Jesus is not fully God and it is little wonder those who insist it is so soon end up denying all manner of biblical teaching as result.