Dietrich Bonhoeffer’s work Ethics was written from 1940-1943. Intended as lectures, this is his most mature work and is considered to be his major contribution to theology. Christian ethics, he says, must be considered with reference to the regenerated man whose chief desire should be to please God, not with the man who is concerned with an airtight philosophical system. Man is not, and cannot, be the final arbitrator of good and evil. This is reserved for God alone. When man tries to decide what is right and wrong his efforts are doomed to failure. Bonhoeffer wrote that “instead of knowing only the God who is good to him and instead of knowing all things in Him, [man] knows only himself as the origin of good and evil.” With this statement, Bonhoeffer entered one of the most difficult philosophical and theological problems in the history of the church: the problem of evil.
Bonhoeffer believed that the problem of evil could only be understood in light of the Fall of mankind.