Earlier this month I went to Egypt for the annual meeting of the commission charged by the 1998 Lambeth Conference of Anglican bishops with the encouragement of the work of Christian unity. Despite the tensions in the Anglican Communion, which challenge its own unity, this commission, drawn from around the world, has worked for almost a decade in a way that has drawn us together and enabled us to see common patterns in the work of Christian unity across the world.

On my journey to Cairo my fellow passengers included a large party of British Muslims going on the haj, the great pilgrimage to the Muslim holy places of Mecca and Medina, and I found myself in an intensely interesting conversation with my Muslim neighbour. He told me of the spiritual significance of the haj to him personally, and described the sequence of events that would make up the pilgrimage. Questioning me about my own Christian faith, he reminded me of the Muslim veneration of Jesus as a prophet. He assured me that he had no problem with school Nativity plays, even though a nervous secular society all too often believed he might, and ought, to have. The most important thing, he said, was that we should live in acknowledgement of the God who had created the Universe, and that we should strive to love and serve that God.

Yes, I told him, that was my concern as well. But, he said, how difficult it was to love a God whom you had not seen. So I explained how for the Christian the unknown God, the source of all life and being, the creator of all, has chosen to reveal Himself, not just in words of prophecy and inspiration, but in going much farther than this. Although, as the Bible emphasises, God is awesome, holy and transcendent, yet that same God discloses Himself, chooses to make Himself known, in the end, in the amazing wonder of incarnation.

St Paul speaks of how we see the glory of God in the face of Jesus Christ. St John, in the prologue to his Gospel, writes of the Word — the creative reason and wisdom of God — becoming flesh, and in that becoming flesh, that incarnation, “we beheld his glory, the glory of the only begotten of the Father, full of grace and truth”. God comes down, as the 14th-century Christian mystic Lady Julian of Norwich reminds us, “to the lowest part of our need”.

The Christmas story is about the wonder and the mystery of incarnation — of God, the source of all that is, emptying Himself, taking upon Himself our human nature. As St Matthew tells us, the child of Mary will be called “Emmanuel”, which means “God is with us”.

St John says that in this child we behold the glory of God. The Hebrew word for glory is kabod, which means the weight, or the gravitas of something, its character and very being. So St John points us at the very beginning of his Gospel to the true identity of Jesus. He is the one in whom we see the glory of God, what John Henry Newman called “God's presence, and His very self, and essence all-divine”. God freely gives himself in the total self-giving of his love into the life of one made in His image, the creator chooses to live and know as a creature. As the poet Robert Herrick put it: “He drest Him with our human Trim, Because our flesh stood most in need of Him.”

Our human faces express our very identity. We recognise each other most especially by our faces. The portrait painter brings out the character of the one whose portrait is painted above all in the face. And so the face of Jesus Christ, in which, as St Paul says, we see the glory of God, is God's human face. It is the face of the child of Bethlehem, the face of the one who looks at Peter in his denial, and Judas in his betrayal. It is the face depicted in countless representations of the child on his mother's knee, or in agony on the cross, or in the Christ, the ruler of all things, the Pantocrator. But the face is the face of the God whose love comes down to the lowest part of our need, that we may be caught to the very heart of His life, the life for which we were made. It is this Divine Love that we celebrate at Christmas.

The Right Rev Dr Geoffrey Rowell is the Bishop of Gibraltar in Europe