During the summer of 1943,  a teenage boy, Jürgen Moltmann, among many other schoolchildren, was defending the city of Hamburg in the midst of terrifying air raids.

Moltmann remembers, 'with my class, I was in a flak battery in the inner city as an auxiliary. It was wiped out, but the bombs which tore away the boy standing next to me spared me. In the night, for the first time I cried out to God. "My God, where are you?" was my question. "Why am I alive and not dead like the others?" 

During 3 years as a POW, I searched for an answer for my question first in the Psalms of lamentation and then in Gospel of Mark. When I came to Jesus' dying cry, I knew, "There is your divine brother and redeemer, who understands you in your godforsakenness." I sought knowledge to give support to my existence and abandoned my interest in physics and mathematics to find it. Auschwitz and Hiroshima disturbed me deeply.'

[Jürgen Moltmann, How I have changed: Reflections on thirty years of theology (London: SCM Press, 1997)].

Thus began the theological pilgrimage of one of the most influential theologians of the century. In one of his works The Crucified God, he describes as his 'attempt to find an answer for a life in Germany "after Auschwitz."' In it, he argues that theology must begin at the foot of the cross where Jesus cried out 'My God, My God, why have you forsaken me?' Moltmann asserts that Calvary forces us to speak about a crucified God who exposes himself to suffering.

The cross reveals another side of God - His vulnerability, because it displays the divine Son suffering and dying in the darkness, forsaken by his Father. Moltmann argues that at the cross, we also see that God is directly affected by suffering.

The cross, which lays bare the innermost being of God, does not therefore reveal an immovable, impassible deity, but rather exposes the passionate, vulnerable heart of the crucified God.

Moltmann's theology demonstrates the significance of the historical, social and cultural context of theology. In his theology Moltmann reflects upon some of the deepest issues raised by the horrors of war. He had reached the same conclusion as Dietrich Bonhoeffer who, in concentration camp, had written 'only the suffering God can help.'