In speaking about costly grace Bonhoeffer was fighting a misunderstanding of Martin Luther’s doctrine on justification, the center of which was the statement that God justifies human beings “through grace alone.” This means that human beings must and can do nothing to be accepted by God. No good moral work, no religious deed can bring about God’s acceptance. God accepts human beings without preconditions and solely out of grace. Human beings must only believe this and acknowledge it. According to