Mediator between God and men, he His Deity equal with the Father, in His flesh, i.e. in His human nature, inferior to the Father, — unchangeably immortal in respect of the divine nature, in which He is equal with the Father, and yet changeable and mortal in respect of the infirmity which was His through participation with our nature.
Augustine, Letter to Volusian, (Letter 137)
‘The Word became flesh’, ‘The Son of God became a baby’, ‘God became man’. These simple English sentences express the mystery of Christmas, the mystery of a true Incarnation. Like other biblical mysteries, we can state simply what the mystery is, using words that a child can grasp. Yet what we express remains unfathomable to the most brilliant of creaturely minds. ‘Great indeed….is the mystery of godliness’. (I tim.3.16) ‘Thanks be to God for his inexpressible gift’ (2 Cor. 9.15) Why is this? What makes the Incarnation so mysterious?
To try to answer that question, we must ask another one: What is a true incarnation? It is God becoming man, taking on human nature – not just a human body, but human nature, body and soul – while remaining God in a wholly undiminished way. We must not think of the Incarnation as the elevation of a mere man. The direction is the other way: not the raising of mankind, but the coming down of God, his condescension. God comes down to us, taking our nature, but remains God in doing so.
This last point is vital for our understanding of the mystery. God became man not in the sense in which a table becomes ashes or eggs become an omelette, but more in the sense in which a man and a woman becomes a husband and a wife when they are married. They remain a man and a woman, but in marrying they enter into a new relation. In a similar, though utterly unique, way the Son of God remains the Son of God and yet enters into a new relation. He becomes united to human nature in the person of Jesus Christ, the Mediator, the God-man. In this union he is so closely united to us – in the closest possible way - that the Incarnation is best thought of as the incarnation of one person with two natures, not (as in marriage) a union of two persons who yet remain distinct. The Incarnation is a mystery quite simply because it is unparalleled in our thought. Not simply a one-off, but a one-off that we cannot get our minds around. Earthly relationships and connections can only be faint analogies of what happened at the first Christmas.
In becoming incarnate God condescends to us. The condescension takes this form: the love and grace of God is seen in being as closely united as it is possible to be to human nature and to all that human nature can undergo – degradation, temptation, weariness, weakness, - yet without sin. God so loved the world that he gave his one and only Son to be incarnate, and in his human nature to suffer these things. In the fact of his suffering, and the manner of it, and the reason for it, we see the glory of God revealed. But not only is the love and grace of God seen, but his purity and holiness and justice too. For our servant king is born to die.
There is a temptation to focus on the baby in the manger as if he were like any other baby. But while baby Jesus was a true baby, he was not only a baby. That’s why it is necessary to concentrate not only on what we think we can picture or visualise about baby Jesus, but on what the Bible tells us about the significance of what we can picture, what it means. We need to focus not only on the events, but also to pay attention to the inspired commentary on those events. The commentary of the angels, and of the godly remnant – Elizabeth, Zachariah, Anna, and especially of Jesus’s mother Mary - of the writers of the Gospels, and of Paul and the other Apostles.
It is important to think of the Incarnation not as God being diminished, as if God lessens or shrinks himself in order to make room for human nature, but as God remaining wholly and fully God. Christianity is a supernatural faith, and one way in which this is shown is by the Incarnation being a true making-flesh of God. (Anther way is by emphasising with Scripture that conversion is a true regeneration by God the Holy Spirit, and not simply a change in mind or character.) So we must never think that by becoming human God is so no longer authentically or fully God. Rather, in incarnation God is veiled. The unimaginable and unbearable glory and power of God is veiled by him taking on human nature in the person of the Son, and so humbling himself. (Phil. 2)
So Jesus Christ is what you get when God condescends to us in this way. Veiled, but not blotted out, not wholly hidden – ‘And we have seen his glory, glory as of the only Son from the Father, full of grace and truth’. (John 1.14) Somewhat paradoxically the veiling is also a revealing of God. For it tells us what God is when his glory is ‘refracted’ by being in union with human nature. Just as a light bulb is one way of showing us what electricity is like, and an electric shock is another way, so the Incarnation is the God-ordained way of showing us what God is like.
He who has seen me has seen the Father. Not only of course is his love and compassion revealed, but also his power over nature. God is also revealed by Jesus’s emotional reactions to the sin and shame of his earthly environment – anger at the money changers and at the hardness of heart and unbelief of the Jewish religious leaders, and deep shock and sorrow at the effects of death on Lazarus and the funeral crowd. And seen in his steely determination to accomplish his Father’s will by his resistance to temptations, including those of his closest disciples, and never to cease to realise his goal as the Suffering Servant.
At Christmastime we are tempted to think that the events of Christmas are the whole story, or to think of a great beginning leading to a tragic end. But Christmas was an event in real time. It is not the illustrating of an eternal value, like good will or humility, or not merely that. For in becoming incarnate the Son of God has begun a ministry which has not even now run its course. He will come ‘a second time, not to deal with sin but to save those who are eagerly waiting for him.’ (Heb. 9. 28) The first Christmas is over and done with. We can recall it, but not call it back. The Incarnation was the beginning of Christ’s earthly ministry; as the Mediator he is crucified, risen and ascended, and in all this God’s grace and glory is revealed. This is what is meant by calling Christianity a ‘historical’ religion; real events are at its heart. Here and now we await the risen Saviour’s coming in great glory.
This is important for a true understanding of Christmas. The Incarnation is not an event that simply embodies certain human ideals, such as love and self-giving service. It is the visible beginning of God’s mighty acts of redemption. There’s a temptation at Christmas to think that the Incarnation is happening all over again. But it cannot be. It occurred in real time, and we live in the light and benefit of it, with more happenings to come. Only then will the scope of the glory and significance of the Incarnation be truly appreciated.