Why did the incarnation happen as it did?

At the centre of Christmas we celebrate the fact that ‘the word became flesh’ (John 1:14). God the Son, the second person of the Trinity, who has existed alongside the Father and the Spirit from all eternity, took human nature upon himself for the sake of our salvation.

According to the accounts given to us in the Gospels of Matthew (Matthew 1:18-22) and Luke (1:26-37 and 2:1-7) the way he took human nature upon himself was through a miracle. In the words of the Apostles’ Creed he was ‘conceived by the power of the Holy Spirit and born of the Virgin Mary.’ What this means is that Jesus had no biological human father. He took his humanity from his mother Mary in whose womb he was conceived by the miraculous action of the Holy Spirit.

The question that is not often discussed is why the incarnation happened this way. Why in his infinite wisdom and goodness did God decide to take human nature upon himself by means of this particular miracle?

There are three misleading answers to this question.

The first is to say that the incarnation happened this way because Jesus’ birth from a virgin is what makes him the Son of God. This answer might seem to be supported by the words of the angel Gabriel to Mary in Luke 1:35:

‘The Holy Spirit will come upon you,

and the power of the Most High shall will overshadow you;

therefore the child to be born will be called holy,

the Son of God.’

However, these words are the angel’s answer to the question asked by Mary in the previous verse ‘How shall this be, since I have no husband?’ In verses 31-33 the Gabriel has told Mary that she will conceive and have a son who will be ‘called Son of the Most High.’ May asks how she can have this son in the absence of a husband and verse 35 supplies the answer. It describes the means by which Mary will conceive her promised son, not the reason why this son will be the Son of God (which is not what Mary asks).

The reason that Jesus will be called the Son of God is because in him created human nature will be united with the eternal divine nature of the second person of the Trinity in one person. The method by which this union will take place will be a virginal conception, but there is nothing to suggest this is the only way that it could have happened and that God the Son could not have united himself with a human nature created through sexual intercourse between a husband and wife. There is no reason why this would have been impossible.

The second is to say that Jesus had to be born of virgin because a holy God cannot be associated with sexual intercourse. The problem with this answer is that in the Bible God is associated with sexual intercourse. It is something which he created at the beginning of time as a means by which husband and wife could be united together and fulfil the divine command to ‘be fruitful and multiply’ (Genesis 1:28, 2:24) and it is the means he regularly uses to cause children to come into existence, whether in the normal course of events, or by means of a miracle as in the case of the birth of John the Baptist from Zechariah and Elizabeth (Luke 1:5-24, 39-66). Saying that the action of God and sexual intercourse are intrinsically incompatible is therefore clearly wrong.

The third is to say that Jesus had to be born of a virgin because otherwise he would have been subject to original sin like the rest of the human race. This answer confuses sexual intercourse as the means by which original sin is passed on from one generation to the next with sexual intercourse as the reason because of which it is transmitted.

Someone who is born as a result of sexual intercourse will be subject to original sin. However, this is simply because sex was the means by which they became a member of fallen humanity as a descendant of Adam. Sex itself is not the reason for their fallen state (as if sexual intercourse created original sin), it is only the channel through which they inherit it.

In addition, even if Jesus had human descent from both Mary and Joseph this would not necessarily have made him subject to original sin. This because without divine intervention the human nature he inherited from Mary would have made Jesus subject to original sin. What preserved him from this was the positive action of the Holy Spirit who enabled him to remain free from sin from his conception onwards. This could, presumably, have been equally true if he had inherited his human nature from both Mary and Joseph.

If we set aside these three misleading answers what can we say about the reason why the miracle of the incarnation took the form it did? The answer is fourfold.

First, the nature of the miracle, which means that Jesus had no human Father, points us to the truth that his father is God since in the unity of his person he is God the Son ‘begotten from everlasting of the Father,’ as Article II of the Thirty Nine Articles puts it. Jesus the Son can save us because he is God and he is God because he has God the Father as his father. This is the first truth to which the miracle of the virgin birth points us.

Secondly, the work of the Holy Spirit in bringing about Jesus’ conception (Matthew 1:18, 20, Luke 1:35) points us to the truth that what is taking place in Jesus is the beginning of a new humanity and a new creation. Just as when the world was first made it was by means of God at work through his Spirit (Genesis 1:2, Psalm 33:6), and when humanity was created the first human (created by God without sexual intercourse) was given life through the Spirit (Genesis 2:7), so also in the birth of Jesus there is through the creative work of the Spirit the beginning of new humanity (with Jesus as the second Adam) as the first fruits of a renewed creation (Romans 8:18-25).

Thirdly, like the story of the birth of John the Baptist with which it is intertwined in the opening chapters of Luke, the story of the miraculous birth of Jesus points us to the truth that the saving grace of God does for us what we cannot do for ourselves.

Elizabeth and Zechariah couldn’t have children because ‘Elizabeth was barren, and both were advanced in years’ (Luke 1:7). Yet what seemed impossible became possible because the action of God enabled them to become the parents of John the Baptist.

Even more radically, Mary couldn’t have a child because, as we have seen, she was unmarried and therefore not involved in sexual intercourse. Yet God took her virginity and used it as a symbol of how salvation, which we are unable to achieve through our own actions, is made possible through the action of the free grace of God. In the story of the birth of Jesus, all human striving and activity, symbolized by the begetting of children through sexual intercourse, is set aside in favour of simply accepting grace as a gift. As  Charles Cranfield puts it:

‘…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).’

In the words of St. Paul, ‘For by grace you have been saved through faith; and this is not your own doing, it is the gift of God – not because of works, lest any man should boast’ (Ephesians 1:8-9).

Fourthly, just as Jesus’ resurrection is the prototype of our resurrection (1 Corinthians 15: 20-23) so also is virgin birth is the prototype of our own virgin birth. This truth is highlighted for us by St. John in John 1:12-13: ‘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 not of the will of the flesh nor of the will of man, but of God.’

The language St. John uses in these verses has a deliberate double reference. He is describing how Christians become children of God, but he describes this process in language that also refers back to the virgin birth of Christ. What he is saying is that through faith and baptism we become children of God through Jesus and this happens through a supernatural work of God that follows the pattern of Jesus own birth. In John 1:13 there is no reference to the work of the Spirit, but this reference is supplied in Jesus’ teaching on the new birth in John 3 to which this verse in John’s prologue looks forward. In John 3:5-8 Jesus tells Nicodemus that that the new birth referred to in John 1:13 comes through the work of the Spirit:

‘Jesus answered, ‘Truly, truly, I say to you, unless one is born of water and the Spirit, he cannot enter the kingdom of God. That which is born of the flesh is flesh, and that which is born of the Spirit is spirit.  Do not marvel that I said to you, ‘You must be born anew.’ The wind blows where it wills, and you hear the sound of it, but you do not know whence it comes or whither it goes; so it is with everyone who is born of the Spirit.’’

In summary, the virgin birth of Christ as recorded by Matthew and Luke points us to four key truths:

  • Jesus is God the Son eternally begotten by God the Father;
  • What is taking place in Jesus is the beginning of a new humanity and a new creation;
  • The saving grace of God does for us what we are unable to do for ourselves;
  • The birth of Jesus is the prototype of our own miraculous re-birth as children of God.

God does all things for a purpose. With God there are no accidents and so we may be sure that the form of the miracle by which Jesus was born into the world was intended by God to point to these truths. This is what he wants us to learn as we think about the manner in which Jesus Christ was born.

M B Davie 15.12.17