For Christians the purpose of Christmas is to celebrate a miracle. The miracle in question is that, in the words of the Apostles Creed, Jesus Christ was ‘conceived by the Holy Ghost, born of the Virgin Mary.’ In this final blog post for 2019 I shall consider the significance of the fact that Jesus came into the world by means of this particular miracle.
The fulfilment of God’s word through Isaiah
The first thing to note is that this miracle tells us that what God says will happen comes to pass. As Matthew tells us: ‘All this took place to fulfil what the Lord had spoken by the prophet: ‘Behold a virgin shall conceive and bear a son and his name shall be called Emmanuel’ (which means, God with us).’ (Matthew 1: 22-23).
Over seven hundred years before Jesus was born, God declared through the prophet Isaiah that the eventual consequence of the unbelief of King Ahaz of Judah would be the collapse of the kingdom of Judah and the end of the Davidic dynasty. However, he also declared that that would not be the end of the story because beyond this disaster something new would take place: ‘a virgin shall conceive and bear a son and his name shall be called Emmanuel’ (Isaiah 7:14).
What the miracle of the virgin birth tells us is that things worked out exactly as God said they would. By the time Jesus was born the kingdom of Judah was no more and the Davidic dynasty had come to an end, and in that situation the Virgin Mary gave birth to a son whose ‘name’ (i.e. whose identity) was ‘God with us’ (‘us’ being the whole human race). 
Jesus’ divinity and humanity
The second thing to note is that this miracle points us to the truth that Jesus Christ is both divine and human. Jesus name is ‘God with us’ because he is God. He is ‘mighty God’ (Isaiah 9:6). He is the divine Word that from all eternity was with God and was God (John 1:1). He is ‘God over all, blessed for ever’ (Romans 9:5). However, his name is also ‘God with us’ because through the miracle of the virgin birth ‘the Word became flesh’ (John 1:14) by taking our human nature upon him.
Jesus divine nature is bestowed on him by God the Father from all eternity. In the words of the Nicene Creed, he is ‘begotten of his Father before all worlds.’ His human nature, however, is something that he possesses because of his birth in time from the Virgin Mary. To quote the Athanasian Creed:
‘…the right Faith is that we believe and confess: that our Lord Jesus Christ, the Son of God, is God and Man:
God, of the substance of the Father, begotten before the worlds: and Man, of the substance of his Mother, born in the world.’
The grace of God in Jesus’ birth and our rebirth
The third point to note is that the particular form of this miracle points us to the truth that both the birth of Jesus and our own subsequent births as children of God are utterly dependent on the gracious activity of God himself.
As Charles Cranfield explains, the fact that Jesus was ‘conceived by the Holy Ghost’ means:
‘…that God himself made a new beginning in the history of his creation by coming in person and becoming part of that history. He himself originated this particular human life, that of Jesus, by a new act of creation. Therefore Jesus Christ is not a saviour emerging from the continuity of our human history, but God in person intervening in history from outside history.’ 
Furthermore, the fact that:
‘… Jesus’ mother was a virgin attests that God’s redemption is ‘by grace alone.’ Here our humanity, represented by Mary, does nothing more than accept, than submit to, being simply the object of God’s grace. That is the real significance of the address ‘favoured one’ to Mary in Luke 1:28. The male, characteristically the dominant and aggressive element of humanity, is excluded from this action and set aside, and in Mary our humanity’s part is simply to be made the receptacle of God’s gift, the object of God’s mercy: ‘Here am I, the servant of the Lord, let it be with me according to your word’ (Luke 1:38).’
When John describes how we become children of God through faith in Jesus he uses language which deliberately recall Jesus’ miraculous birth in order to emphasise that our new birth is likewise a result of divine rather than human activity. As with Mary, so with us, the role of human beings is simply to believe in and accept the gift of new life that God gives to us. ‘But to all who received him, who believed in his name, he gave power to become children of God; who were born not of blood, nor of the will of the flesh, nor of the will of man, but of God’ (John 1:12-13).
What all this means for us
For us as Christians today, the way that Jesus’ birth fulfilled the word of God spoken through Isaiah reminds us that we can always trust God to do what he says he will do. This means that we can rely on his promises given to us in Scripture that through Jesus he has rescued us from sin and death and will enable us in due time to live with him for ever in his eternal kingdom.
Secondly, the fact that Jesus is both divine and human means that we have both an all powerful saviour who is able to perform what God has promised, and a sympathetic saviour who understands our human weakness and fragility from the inside. ‘For we have not a high priest who is unable to sympathize with our weaknesses, but one who in every respect has been tempted as we are, yet without sin. Let us then with confidence draw near to the throne of grace, that we may receive mercy and find grace to help in time of need’ (Hebrews 4:15-16).
Thirdly, the fact that both the birth of Jesus and our rebirth as children of God are gracious gifts that we as humans did nothing to achieve highlights our need for humility. We need to constantly recall that we have been saved by grace and that our calling is simply to be thankful and to express our thankfulness in lives of joyful obedience.
 For this interpretation of Isaiah 7:14 see J A Motyer. ‘Content and context in the interpretation of Isaiah 7:14,’ Tyndale Bulletin 21, 1970, pp.118ff.
 Charles Cranfield, The Apostles’ Creed (Edinburgh: T&T Clark, 1993), p.30.
 Cranfield, p.30.