The Crucified God: The Cross of Christ as the Foundation and Criticism of Christian Theology by Jürgen Moltmann raises the question of God’s suffering. As the theologian approaches this controversial issue, he deals with the Greek concept of apatheia (impassibility) of God. He says,

In the ancient world, early Christianity encountered apatheia as a metaphysical axiom and an ethical ideal with irresistible force.

Plato rejected the old Greek idea of the gods being capricious, vengeful, envious, and vindictive, contrasting the passions to catharsis—that is, the purification of emotions. He believed that the ability to suffer was inconsistent with God’s perfection. Although Christianity is all about God the Son’s sufferings (passion), it inherited this Platonic drift toward the idea of God being incapable of suffering. However, the question of God’s suffering has surfaced in theological polemic more than once during church history.

Patripassianism (the teaching about God the Father literally sacrificing himself on the cross) was rejected early on by both the Church, both in the east and in the west. Rather than resurrecting this disputable ancient teaching, Moltmann reaffirms God’s capability of suffering and sympathizing with sufferers. And yet the Son dying as the Father forsakes him is something different from the Father suffering at the Son’s death. The Son endures the dying, while the Father suffers because of the Son’s death.

As he develops his argument, Moltmann talks about the unique character of Christian faith—which finds its identity in the cross—among other religions and ideologies.

Faith in the cross distinguishes Christian faith from the world of religions and from secular ideologies and Utopias, in so far as they seek to replace these religions or to inherit their legacy and bring them to realization. But faith in the cross also distinguishes Christian faith from its own superstitious manifestions. The recollection of the crucified Christ obliges Christian faith permanently to distinguish itself from its own religious and secular forms.

Moltmann does not criticize other religions or atheism as such. He talks about protest atheism, for example, and rather than refuting it, he goes beyond it. On the other hand, he shows that traditional theism cannot be the answer to the question of suffering and of God’s righteousness. He explains that the church needs to distinguish itself from the “Christian-bourgeois world.” If it is not measured by the criterion of the cross, Christianity loses its identity and becomes confused with the surrounding world and its agendas. Natural theology, the one that proceeds from the existence of this world and the facts of nature, cannot be the center of Christian faith.

As Moltmann moves to the issue of the cross as it applies to political liberation of mankind, he says,

The kingdom of God can be socialism, but that does not mean that socialism is now the kingdom of God.

Just as atheism is not to be rejected out of hand, socialism positively reflects something from the pattern of God’s ideal for the world. Christian faith can find parables of God’s kingdom not only in its own agendas but also in other social movements, including socialism. Socialism as political and economical order can be a phase—albeit imperfect—on the way towards the realization of the kingdom of God. And, as Moltmann himself believes, it can be a “symbol of liberation from the vicious circle of poverty.” Yet we cannot equate it with the kingdom of God in its fullness. According to Moltmann, the teaching of God’s suffering with the whole of humanity helps to understand the historical process and to open the way towards the transformation of society.