Some time last week, I had a look at one of the ways some of us tend to wander into heresy around Christmas. Jesus was a real human, who entered our world limited by all the things you would expect a human baby to be limited by. His deity didn’t somehow override his humanity. He was really, actually human.
Others, however, want to diminish Jesus’ deity. They want to insist that Jesus assumed our fallen human nature. But unlike most humans, Jesus did not have a biological human father. He was born of the Holy Spirit. The only man ever to have been born of the Spirit. The virgin birth was necessary because, had he been born of a biological human father and the Spirit merely came upon him later, he would necessarily have inherited Adam’s sinful nature. Jesus did not inherit Adam’s sinful nature, and was not guilty before God by nature.
There are, of course, several problems with this. If Jesus was merely born like everyone else, then he is nothing more than a mere man. Whilst he was fully man, the Bible is quite clear that he is also fully God. But if Jesus was born like everyone else, then he is just a man like everyone else. Even if we believe the Spirit descended on him later (as some ancient heresies argued), unless you believe we all become little gods when the Spirit takes up residence in us, there is no reason to assume that would deify Jesus. A normal birth means Jesus is a normal man and nothing more.
The problem here is that sin is infinitely offensive to a holy God. If Jesus is a mere man – even if he somehow managed to live a perfect human life – he could still only pay for sin in the same way as any other finite human being; namely, finitely. But an infinite offence requires an infinite price to be paid, requiring an infinite person to pay it. If Jesus is just a man, he cannot pay the sacrifice for sin. There would never be a time when he could say, ‘it is finished’ because the infinite price would never have been paid.
On top of that, a normal birth, as a normal man, means Jesus does inherit Adam’s sin nature. The problem here is that undermines Jesus’ impeccability; the doctrine of Jesus’ sinlessness. Jesus would be guilty before God because he would have inherited Adam’s guilt and also would have sinned personally because a sin nature can do nothing else.
That has the problematic knock-on effect of rendering Jesus’ sacrifice for sin ineffective anyway. If Jesus had a sin nature, and therefore inevitably sinned, he would not have lived the perfect life and died the perfect death required. Sin would not be defeated; Jesus would have been! His attempt to keep and fulfil the law of God in its entirety would have failed in the way every type that came before him failed to do it too. Jesus would have simply been the latest in a long line of potential messiahs who failed in the one requirement demanded of them, perfect faithfulness and covenant keeping.
As I have said here:
The virgin birth provides the only way for Jesus to avoid both the imputed guilt of Adam and the problem of Total Depravity. The Bible tells us he was born of a virgin, conceived by the Spirit. This means he had no earthly father from whom he would inherit Adam’s imputed guilt and was, from birth, born of the Spirit meaning he had no sinful nature.
Perhaps worst of all, if we maintain that Jesus was both fully God and fully man, to deny the virgin birth would lead us to the conclusion that God is evil and sinful. If Jesus inherited Adam’s sinful nature and suffered from the effects of Total Depravity, not only would it be possible for him to sin, it would have been impossible for him not to! That leads us to the conclusion that God himself is sinful because Jesus, as God, would have been able to sin and active in doing so.
For these reasons, the doctrine of the virgin birth is important:
If the virgin birth isn’t true; God is potentially evil and Jesus (and, by extension, God) is certainly sinful. Jesus cannot impute righteousness and thus is incapable of saving anyone. All who worship God and serve his glory are serving his inherent evilness. In essence, Christianity loses any value whatsoever.
But, of course, Jesus is not a mere man. He was born of the Spirit to a virgin so, as the God-man, he did not inherit Adam’s guilt nor his sinful nature. Not only did he not sin, it was impossible for him to do so as the eternal second person of the trinity. This means that his infinite divine nature could offer the infinite sacrifice required to pay for sin. He could live the sinless life required, faithfully keeping covenant, and die in the place of all who believe in him. He was an acceptable mediator between God and man, being fully God and fully man himself.
We shouldn’t deny either the humanity of deity of Jesus. He was both fully God and fully man. And both really matter.