Then Pilate said to him, “So you are a king?” Jesus answered, “You say that I am a king. For this purpose I was born and for this purpose I have come into the world — to bear witness to the truth. Everyone who is of the truth listens to my voice.” (John 18:37)
This is a great Christmas text even though it comes from the very end of Jesus’s life on earth, not the beginning.
Notice: Jesus says not only that he was born, but that he “came into the world.” The uniqueness of his birth is that he did not originate at his birth. He existed before he was born in a manger. The personhood, the character, the personality of Jesus of Nazareth existed before the man Jesus of Nazareth was born.
The theological word to describe this mystery is not creation, but incarnation. The person, not the body, but the essential personhood of Jesus existed before he was born as man. His birth was not a coming into being of a new person, but a coming into the world of an infinitely old person.
Micah 5:2 puts it like this, 700 years before Jesus was born:
But you, O Bethlehem Ephrathah, who are too little to be among the clans of Judah, from you shall come forth for me one who is to be ruler in Israel, whose coming forth is from of old, from ancient days.
The mystery of the birth of Jesus is not merely that he was born of a virgin. That miracle was intended by God to witness to an even greater one; namely, that the child born at Christmas was a person who existed “from of old, from ancient days.”
And, therefore, his birth was purposeful. Before he was born he thought about being born. Together with his Father there was a plan. And part of that great plan he spoke in the last hours of his life on earth: “For this purpose I was born and for this purpose I have come into the world — to bear witness to the truth. Everyone who is of the truth listens to my voice” (John 18:37).
He was the eternal Truth. He spoke only the truth. He acted out the greatest truth of love. And he is gathering into his eternal family all those who are born of the truth. This was the plan from ancient days.
– John Piper