When Mary has said “yes” to God’s request, she sings, with joy, of what she has discovered about God. Her famous song, the Magnificat, tells of the God who chooses to work through an insignificant girl like her.

This God is greater and more powerful than any of the world’s rulers; this God is always faithful to the promises he has made; and yet this God is hard to fathom, and his priorities are incomprehensible. He is not very interested in the power­ful and proud, only in the poor and needy.

The choice of Mary as his accom­plice is just the beginning of the strange and opaque way in which God comes to save the world. So much is left to chance; so little thought is apparently given to secur­ity and success.

When God comes to live with us in the world that he has made, he comes as a baby, at a time when in­fant mortality rates are high; he is born not in the safety of a home, with staff ready and waiting, but just wherever his parents could find shelter.

We are told that the new baby was put to sleep in an animal feed­ing trough; so, in his painting (above, right) Paolo Schiavo shows the ox and the ass, who have come to feed, but have stayed to worship. They gaze down at the baby with such gentleness and compassion, and the baby looks back, not at all afraid, enjoying their warm breath on his face.

But if the animals know what they are seeing, that does not seem to be the case with people. Only the oddest of people are called to wit­ness his birth.

Shepherds are summoned from their flocks. These dirty, smelly, uncouth herdsmen — whom re­spect­able villagers avoided, and who had a universal reputation in Jesus’s day as vagabonds and thieves — receive a personal invitation from the angelic hosts of heaven to come and witness the birth of Jesus. Why shepherds? They have no in­fluence; no one will listen to their testimony. But, like Mary, they praise the God who thinks that they are worth bothering with.

Jesus’s other strange visitors do not come by angelic invitation. They follow a sign that ought to have been visible to all and sundry. Foreign­ers arrive, following the path of an unusual star. Traditionally, they are called “Wise Men”, or “Magi”, or even “kings”. Certainly, they must have been fine astronom­ers, and wealthy enough to set off on this strange journey in search of the newborn child who merited his own star.

It is hardly the fault of the Wise Men that they expected to find Jesus at court — after all, who but a great ruler would receive such attention from the heavenly powers? They do not know the character of God as Mary and the shepherds have come to do.

So perhaps it is even more to their credit that when they see Jesus, they recognise him, and pay him the homage due to a king. They leave their portentous gifts — gold for a king, frankincense for a god, and myrrh for a death — and depart. Who knows if they ever told what they had seen and, if so, whether they were believed?

SO GOD’s methods at the birth of Jesus look strangely ineffi­cient. He asks Mary to be his main collaborator; he sends angels to invite shepherds as his witnesses; and he sets a star in the heavens, and leaves it to fate to see who has the insight to make sense of the sign.

Mary’s intuition about God — that he doesn’t care much for the mighty but sees the humble and weak in all their glory — is to be borne out all through Jesus’s life, right up to the time of his bitter death. And that death is prefigured in the odd gifts that the Wise Men bring.

Artists often try to hint at the connection between the way in which Jesus is born and the way in which he is going to die. There is an extraordinary sand sculpture by Núria Vallverdú which depicts the nativity of Jesus as the Last Supper (above). The child sits with bread and a cup in front of him, with the shepherds and Wise Men clustered on one side of the table, in a forma­tion very like Leonardo da Vinci’s famous picture of the Last Supper.

The child sits in his throne, gazing out at us pensively, as though contemplating what must come. Jesus is born to offer his life for us: the death is prefigured in the birth.

The Gospel-writers try to help us to see what God is doing in allowing Jesus to be born in this way. They describe the world around the child. He is born in occupied territory, under the rule of the mighty Roman Empire. The emperor, Augustus, was hailed as the “saviour” of the world, to whom all the people of the empire owed tribute, enforced by sheer power, if necessary.

This empire believed that it knew, and indeed invented, all the struc­tures of power which were necessary for human beings. Its huge, disci­plined, ferocious army was not afraid to use brutally effective methods to ensure that no challenge to the power of Rome could be successful.

For the convenience of Rome, Jesus is born where he is, as his parents, like tiny insects swept away by a flood, are made to travel to register where the Romans tell them to. The Romans certainly do not notice the significance of one birth among so many.

The local ruler of the country where Jesus is born knows all about Roman power, and does whatever is necessary to get his share of it. The Romans gave power to local puppet rulers when it suited them, and Herod was one such.

Herod does have his suspicions raised by the Wise Men. He senses a challenge to his authority when these strangers come looking for a king. So he takes his own measures to ensure his continuing control: he orders his soldiers to kill any boy-child of roughly the right age.

That is the kind of power recognised by the world into which Jesus is born. And that is still, on the whole, the kind of power we understand. But God’s whole action in Jesus is a direct challenge to that kind of power. God, the maker and ruler of the universe, calls Mary and the shepherds to be part of his most powerful act: coming to live in the world that he has made.

This is the third of four edited extracts from Faces of Christ by Jane Williams (Lion, £9.9; (CT Bookshop £9); 978-0-7459-5522-3).