In his chapter on Shame and Conscience, Bonhoeffer says that man is reminded of his dis-union with God in shame. Conscience is man’s disunion with himself and it relates to himself and is not concerned with God and other men. Conscience is satisfied when the prohibition is not disobeyed. Whatever is not forbidden is permitted and for conscience, life falls into two parts: what is permitted and what is forbidden.
There is no positive commandment and what is permitted for conscience is identical with good and it does not register the fact. And even in this man is in a state of disunion with his origin. The range of experience of conscience does not extend to the fact that this unity itself pre-supposes disunion with God and with man and that consequently beyond the disobedience to the prohibition, the prohibition itself, as the call of conscience, arises with disunion from the origin.
This means that conscience is not concerned with man’s relation to God and to other men but with man’s relation with himself. Bearing within himself the knowledge of good and evil, man has become judge over God and man just as he is judge over himself. Man begins to reflect upon himself while he starts knowing of good and evil in disunion with the origin and in conflict, the judge is invoked and the judge is the knowledge of good and evil which is the man.
Bonhoeffer, Dietrich. Ethics. New York, NY: Touchstone, 1955.