The appalling tragedy of the Asian tsunami must surely shake the faith of the most committed believer. The Rev Paul Walker, a regular contributor to The Northern Echo's Saturday Sermon, explains how he reconciles the events with his faith in God.

It all began with a massive earthquake under the Indian Ocean. I haven't quite grasped the science, but it grew into an enormous tidal wave. In many different ways that tidal wave has washed over us all.

On one side of the world it has brought unprecedented death and destruction, here, on the other side, it has brought unprecedented care and generosity. For the first time in their lives my teenage daughters spontaneously reached into their own pockets.

Now, as we are beginning to settle into 2005, the horror of what we have seen and heard is sinking in. Most of us have started to reflect on how this could have happened and whether it has any meaning at all. The sheer number of people who have died is unimaginable and each one is a tragedy in itself. And, for once, we can't blame war or global warming. This is a natural disaster which started in the earth. If anyone is to blame it is God.

A natural disaster like this reminds me of a classical argument against the existence of God.

Let me put this simply. Within the Christian tradition, God is considered to be both all-loving and all-powerful. Now consider the tsunami. If God is all-powerful, then either he caused this disaster or he allowed it to happen, in which case he is not all-loving. On the other hand, if God is all-loving but could not prevent this disaster, then he is not all-powerful. The logic of this argument is very persuasive and I have no intention of defending an all-loving/all-powerful God.

Such an enormous disaster takes its toll on many ways of thinking. It can challenge all kinds of belief. Take, for example, a traditional atheistic understanding of the world, which comes across as agonisingly callous. In such thought, things happen for scientifically explicable reasons but have no purpose or meaning and people die, that's it. It can even be argued that such natural disasters help counter-balance the over-population of the world. Somehow you can't imagine such an explanation being much comfort to a person who has just witnessed the death of their children.

For most of us, any attempt at explanation comes woefully short. We are left speechless in the face of such tragedy - but we still strive to understand. Survey after survey gives the surprising fact that most people in Britain still believe in God.

The problem is that we have trouble being able to define what we mean when we talk about God. We have a sense that there is an overriding purpose to life, perhaps we believe that there is a spiritual presence which we have felt. Furthermore, we know that the picture of an old man in the sky with a long white beard is not really what we mean when we talk about God.

So it is that, throughout history, people have attempted to define God, to explain God. Yet all our explanations are just that, human explanations. They are word pictures of the mystery and the power that lies at the heart of the universe and our own being.

Once we acknowledge this, we can be confident in saying that the definition of God as all powerful and all-loving is a human opinion and not necessarily the nature of God. Something like the tsunami challenges human descriptions of God. Hopefully, we are made to rethink what the word God might actually mean. Because, if the word God means anything at all, we humans will never fully understand it, let alone be able to define it.

A tragedy on such a large scale has then challenged what we believe about God. But God won't go away; after all we cried out to God didn't we? I watched interviews with survivors where almost all said that they found themselves praying. It is likely that many of these people were not religious. How many of us faced with the possibility of imminent death would not pray?

Meanwhile, many of us found ourselves watching the news and saying, in one way or another, "Oh my God".

Personally, I find speculation about the nature of God in such a crisis to be pointless. The primary question that the tsunami raises is the far more basic "what can I do?"

Over the last few days, I have found myself glued to television as the full horror of what has happened has emerged. Horrific pictures, the death of British holidaymakers alongside thousands of others and the terrible stories I have heard have all brought me to my knees.

I do not know what to think but I know how I feel. My faith compels me to pray and to give. I can do little else. And if I am honest about my prayer, I have been very angry with God. How could such a thing happen, why did you allow it?.

And in all of this, I am reminded of a story that appears in St Matthew's Gospel in the Bible. The story is set at the end of time when God judges all the nations, when people are divided as sheep are divided from goats. Some are judged well and others are judged badly, but neither can understand how the judgement has been made.

God explains that his judgement is based on what people have done for the hungry, the thirsty, strangers, the naked, the sick and prisoners. God said that feeding the hungry, giving a drink to the thirsty, taking in strangers, clothing the naked, looking after the sick and visiting prisoners are the same as caring for him. In the story those who have done such things are rewarded and those who have not are condemned.

The story seems to be saying that God is more concerned with what we do than what we think. The outpouring of generosity by the British people shows a deeper level of compassion than I had imagined possible.

People of all faiths and none have felt an urge to help; our common humanity will not let us turn away. We may question our motives but we have tried to feed the hungry, give drink to the thirsty, clothe the naked and take care of the sick.

One of the ironies of the tsunami was that it happened on Boxing Day, when most of us were recovering from the over-consumption of food and drink. Every year people question if we understand the real meaning of Christmas. I was left to conclude that the generosity shown to the victims was far more in keeping with the Christmas spirit than whether or not people went to church. Let us further pray that the money so generously given will be as effectively used.

* The Rev Paul Walker is Chaplain to St Luke's Hospital, Middlesbrough.