What is left when the waters have receded? We will all have in our minds the pictures we saw in December and January of a landscape of wreckage and horror. For many here, that will be a picture of how they felt as they first faced the reality of loss, or the fear of hearing the worst – standing in a ruined world, familiar landmarks destroyed, numb with loss. And so often in the middle of this terrible landscape, people feel a sort of irrational guilt: why am I still alive? Why couldn't I protect the people I love? But when the whole world seems irrational, when a disaster sweeps down from nowhere, it isn't surprising that people have unreasonable reactions. What could a sensible reaction possibly be in such a world?

More than four months on, what does the landscape look like? Perhaps it has become quieter inside for some – not calm, maybe not resigned, but slowly getting used to a pain that can never be denied. The anger and helplessness will still be there – anger at God, maybe, and helplessness in the face of a world where totally unreasonable tragedy falls on the unsuspecting and innocent. But, inside and outside, things have altered. For each of us, decisions have had to be taken: what do I do with this, what do I make of it?

Today what is in our minds won't be only that dreadful picture of the day after. Something has grown up in the landscape that is different. Everyone will be aware of the immediate work of emergency rescue services, of personal acts of sacrificial courage, and of the almost unmanageable flow of practical help that has poured out towards the areas most seriously affected. Many in this cathedral will be aware of how many families whose lives were touched by the tragedy have responded by setting up trusts and projects in memory of those they have lost. In the territories devastated by the disaster, reconstruction slowly moves ahead, and the endlessly patient people of these poor and struggling communities rebuild their lives, while their governments take stock of how they can use the opportunity to improve health care and deploy the funds that have come in for the general development of their countries.

So what is left when the waters have gone down again? Continuing and urgent need and pressure to rebuild, yes; continuing pain and, for many people, still anger and bewilderment; but also a landscape where compassion and practical love have grown. In a famous poem, Philip Larkin said, 'What will survive of us is love'; but this is true not only in the rather wistful sense that the memory of love survives when other things about us have been forgotten. It is true in the sense that love can continue to grow even on the soil of the worst pain and the deepest doubt. When we stretch and torment our minds over the problem of evil in the world, we should not forget that the survival of love is just as much of a mystery.

Human beings constantly seem to act as if love were worthwhile – never mind whether it 'works', whether it succeeds in keeping people safe. And the basic story of Christian faith goes further and speaks of a God who acts as if love were worthwhile, despite the fact that it leads to what looks like the most hopeless and violent of failures. Acting as if love mattered, despite everything, is, for the believer, a sign that people are at some level deeply in tune with the reality that underlies the whole universe. We might feel far easier in our minds if the power of God were always visible in safety and success, so that we could always know that love and generosity would win the day. It isn't that sort of world; yet the action of God in the world is always there, always making love possible. The world seems senseless, suffering seems arbitrary and meaningless; yet it is not allowed to be the last word. When the waters have gone down, something still stands. The world is not safe and love cannot guarantee success in the short term; but what love can do is never exhausted.

That is why we are here today – why we are here in a place of worship, not just anywhere, in order to remember the terrible events of December 26th. Somewhere, whatever our level of faith or doubt, we need a place where we can say something about what is left when the waters have gone down, where we can affirm the fact that love survives, and so renew our hope. We are giving ourselves time to notice what so often escapes us – that the human response to pain and tragedy is as 'unreasonable' as so much of the tragedy itself. It is generous and creative, self-forgetful, capable of doing what sometimes seem very small or ineffectual things simply because they are worth doing for the sake of honouring other human beings. Religious believers will say that these 'unreasonable' responses are in fact the most reasonable of all – actions that echo the fundamental act of divine love. Despite all the ways in which we train ourselves out of it by selfishness and busyness, love is essentially the most natural thing for us. And because it is rooted in God's action and doesn't depend on the way things happen to turn out in the universe, it will be battered and hurt, crucified and abused – but not finally destroyed.

'What will survive of us is love'*; because what is most real and active at the very roots of our existence is the unceasing action of God. As we once more face and feel the depth of grief, as we face again our anger or doubt, we also recognise the bewildering mystery of the fact that the ruined landscape can still be made into a place of human dignity and hope. We confront not only the problem of evil but the problem of good, the challenge of love. And we thank God for that challenge; because he is there for people in and through the chaos, we can find the strength to go on building with him a future where such dignity and hope can take root and flourish.

* An Arundel Tomb by Philip Larkin

© Rowan Williams 2005