‘Human beings are called to share the suffering of God in a godless world. Therefore we must really live in the godless world; and may not make the attempt to somehow conceal, to transfigure its godlessness religiously; we mus live in a “worldly” fashion, which means we are liberated from false religious attachments and inhibitions. ‘Being a Christian does not mean being religious in a certain way, or, on the basis of some methodology, to make something out of ourselves (a sinner, a penitent, a saint); rather, it means to be a human being. It is not the religious act that makes the Christian, but participation in the suffering of God in the life of the world. This is the reversal: not to think first of our own needs, questions, sins, and anxieties, but to let ourselves be pulled into the way of Jesus, into the messianic event that is now fulfilled (Isa. 53:4-5).’
– Dietrich Bonhoeffer
Here Bonhoeffer goes beyond grounding responsible action in the reality of Christ – here he grounds being human in Christ. To be a Christian is to truly be a human, and to be human is to be a Christian. One must be in Christ to participate in reality and to participate in the suffering of God. For Bonhoeffer this is the only way to truly even live in any meaningful way – the reality of Christ is his starting point and grounding presupposition. So not only is responsible action grounded in Christ, but the very state of being human is as well.
This is a pretty radical view – Bonhoeffer doesn’t take the easier route of saying that existence is meaningless without God; he denies that one can even exist in any meaningful sense without God. In a way Bonhoeffer also connects human being to suffering – God’s suffering in the world.