'There went out a decree from Caesar Augustus'; we've very likely heard those words many, many times in carol services, like an overture to the great drama of the Christmas story. The emperor Augustus would have been delighted, I'm sure, to be told that his name would still be recalled after twenty centuries - but more than a little dismayed that it would be simply because he happened to be around at the time of Christ's birth. There were all sorts of things for which he would have wanted to be remembered, and many of his contemporaries were not slow in telling him about them. And in fairness he had quite a good claim to fame: he had, after all, restored order to the Roman state and consolidated its global influence as never before. For many decades, a kind of peace prevailed from Germany to Syria – enforced by typical Roman brutality when any signs of dissent appeared, but still probably better than the chaos of the Roman civil war that had been going on before. It made sense to hail him as restorer of peace, and to look forward to a long period of stability and prosperity.

It didn't turn out quite like that, of course; but Augustus's reign was for many people a sort of golden age. In later generations, new emperors set themselves the goal of bringing back something of that stability and confidence, and they would describe themselves on their coins and statues as the rescuers of the world's good order – as 'saviours': something that had already been common among the kings of the Middle East in earlier centuries.

So if you'd asked people of Jesus' day what the word 'saviour' meant, the answer would be pretty plain. It was someone who would bring back the golden age, who would put an end to conflict; you could almost say it was someone who would stop things happening. Salvation was the end of history, brought about by one unique charismatic leader.

Curious that, all these years later, the same language still survives. Twentieth century totalitarian systems looked forward to a state of things where all conflict was over and change and struggle stopped. On the other side, after the end of the Cold War, some scholars were writing about the 'end of history', and an American President spoke of a 'new world order'. In recent weeks, we've seen some of Barack Obama's advisers and colleagues warning about the level of messianic expectation loaded on to the President-elect - wisely recognising the risks involved in tapping in to this vein of excited imagination always just below the surface of even the most cynical society. We have certainly not, as human beings, grown out of the fascination of saviours who will restore the good times. The Lord has bared his arm and is once and for all returning to Zion; surely that is real salvation?

And as always the gospel comes in with a sober 'Yes, but...' The saviour arrives, but goes unrecognised. He is hidden in the form of poverty and insecurity, a displaced person. Instead of peace and the golden age restored, there is conflict, a trial, a cross and a mysterious new dawn breaking unlike anything that has gone before. He was in the world and the world did not know him. Yet to those who recognise him and trust him, he gives authority (not just 'power', as our translations have it) to become something of what he is – to share in the manifesting of his saving work.

So what's happening here to the idea of a saviour? The gospel tells us something hard to hear - that there is not going to be a single charismatic leader or a dedicated political campaign or a war to end all wars that will bring the golden age; it tells us that history will end when God decides, not when we think we have sorted all our problems out; that we cannot turn the kingdoms of this world into the kingdom of God and his anointed; that we cannot reverse what has happened and restore a golden age. But it tells us something that at the same time explodes all our pessimism and world-weariness. There is a saviour, born so that all may have life in abundance, a saviour whose authority does not come from popularity, problem-solving or anything else in the human world. He is the presence of the power of creation itself. He is the indestructible divine life, and the illumination he gives cannot be shrouded or defeated by the darkness of human failure.

But he has become flesh. He has come to live as part of a world in which conflict comes back again and again, and history does not stop, a world in which change and insecurity are not halted by a magic word, by a stroke of pen or sword on the part of some great leader, some genius. He will change the world and – as he himself says later in John's gospel – he will overcome the world simply by allowing into the world the unrestricted force and flood of divine life, poured out in self-sacrifice. It is not the restoring of a golden age, not even a return to the Garden of Eden; it is more – a new creation, a new horizon for us all.

And it can be brought into being only in 'flesh': not by material force, not by brilliant negotiation but by making real in human affairs the depth of divine life and love; by showing 'glory' – the intensity and radiance of unqualified joy, eternal self-giving. Only in the heart of the ordinary vulnerability of human life can this be shown in such a way, so that we are saved from the terrible temptation of confusing it with earthly power and success. This is, in Isaiah's words, 'the salvation of our God' – not of anything or anyone else.

For those who accept this revelation and receive the promised authority, what can be done to show his glory? So often the answer to this lies in the small and local gestures, the unique difference made in some particular corner of the world, the way in which we witness to the fact that history not only goes on but is also capable of being shifted towards compassion and hope. This year as every year, we remember in our prayers the crises and sufferings of the peoples of the Holy Land: how tempting it is to think that somehow there will be a 'saviour' here – a new US president with a fresh vision, an election in Israel or Palestine that will deliver some new negotiating strategy...It's perfectly proper to go on praying for a visionary leadership in all those contexts; but meanwhile, the 'saving' work is already under way, not delayed until there is a comprehensive settlement.

This last year, one of the calendars in my study, one of the things that provides me with images for reflection e very day, has been the one issued by Families for Peace – a network of people from both communities in the Holy Land who have lost children or relatives in the continuing conflict; people who expose themselves to the risk of meeting the family of someone who killed their son or daughter, the risk of being asked to sympathise with someone whose son or daughter was killed by activists promoting what you regard as a just cause. The Parents Circle and Families Forum organised by this network are labouring to bring hope into a situation of terrible struggle simply by making the issues 'flesh', making them about individuals with faces and stories. When I have met these people, I have been overwhelmed by their courage; but also left with no illusions about how hard it is, and how they are made to feel again and again that they come to their own and their own refuse to know them. Yet if I had to identify where you might begin to speak of witnesses to 'salvation' in the Holy Land, I should unhesitatingly point to them.

In any such situation, the same holds true. In recent days, I have been catching up with news of other enterprises in the Holy Land, especially from the Christian hospitals in Bethlehem and Nazareth, struggling with all kinds of pressure on them from various sources and with the chronic problem of desperately small resources, yet still obstinately serving all who come to them, from whatever background. And last week I spoke with someone helping to run a small community theatre project in Bulawayo, supported by local churches, working to deepen the confidence and the hope of those living in the middle of some of the worst destitution even Zimbabwe can show. Signs of salvation; not a magical restoration of the golden age, but the stubborn insistence that there is another order, another reality, at work in the midst of moral and political chaos; the reality that is the eternal 'Logos', St John's Greek term that means not simply a word but a pattern of harmonious relation.

That is what is made flesh at Christmas. And our own following of the Word made flesh is what gives us the resources to be perennially suspicious of claims about the end of history or the coming of some other saviour exercising some other sort of power. To follow him is to take the risks of working at these small and stubborn outposts of newness, taking our responsibility and authority. In the months ahead it will mean in our own country asking repeatedly what is asked of us locally to care for those who bear the heaviest burdens in the wake of our economic crisis – without waiting for the magical solution, let alone the return of the good times. Internationally, it is remembering that our personal involvement in prayer and giving is utterly essential, whatever pressure we may rightly want to bring to bear on governments and organisations.

Isaiah looked towards the day when the guards on the deserted city's wall would see the return of the Lord 'face to face'. So much of our witness to salvation depends on this face to face encounter (and yes, that was one of the ideals that helped to shape the work of this year's Lambeth Conference). We can't pass the buck to Caesar Augustus, Barack Obama or even Canterbury City Council – though we may pray for them all and hope that they will play their part in witnessing to new possibilities. To follow the Word made flesh is to embark, with a fair bit of fear and trembling, it may be, on making history - not waiting for it to stop. And that means speaking and working for Christ in the myriad face to face encounters in which he asks us to be his witnesses – to see and to show his glory, the glory as of the Father's only Son, full of grace and truth.

© Rowan Williams 2008