Why is it often easier for us to acknowledge our sins before God than before another believer? God is holy and without sin, a just judge of evil, an an enemy of all disobedience. But another Christian is sinful, as we are, knowing from personal experience the night of secret sin. Should we not find it easier to go to one another than to the holy God? But if that is not the case, we must ask ourselves whether we often have not been deluding ourselves about our confession of sin to God–whether we have not instead been confessing our sins to ourselves and also forgiving ourselves. And is not the reason for our innumerable relapses and for the feebleness of our Christian obedience to be found precisely in the fact that we are living from self-forgiveness and not from real forgiveness of our sins? Self-forgiveness can never lead to the break with sin. This can only be accomplished by God’s own judging and pardoning Word.
– Dietrich Bonhoeffer, Life Together, cited in David Watson’s Called & Committed, pp. 32-33.