'An understanding of people as sinners enables a pastoral ministry to function without anger. Accumulated resentment (a constant threat to pastors) is dissolved when unreal - that is untheological - presuppositions are abandoned. If people are sinners then pastors can concentrate on talking about God's action in Jesus Christ instead of sitting around lamenting how bad the people are...
But a pastor is not likely to find this view of people supported by the people themselves. They ordinarily assume that everyone has a divine inner core that needs awakening. They're Emersonian in their presuppositions, not Pauline. They expect personal help from the pastor in the shape of moralistic, mystic, or intellectual endeavours. People don't reckon with sin as that total fact that charcaterizes them; nor do they long for forgiveness as the effective remedy. They yearn for the nurture of their psychic life, for a way in which they may bypass grace and walk on their own...
The happy result of a theological understanding of people as sinners is that the pastor is saved from continual surprise that they are in fact sinners. It enables us to heed Bonhoeffer's admonition: "A pastor should not complain about his congregation, certainly never to other people, but also not to God. A congregation has not been entrusted to him in order that he should become its accuser before God and men." So sinner becomes not a weapon in an arsenal of condemnation, but the expectation of grace. Simply to be against sin is a poor basis for pastoral ministry. But to see people are sinners - as rebels against God, missers of the mark, wanderers from the way - that establishes a basis for pastoral ministry that can proceed with great joy because it is announcing God's great action in Jesus Christ - "for sinners."'
Eugene H Peterson, The Contemplative Pastor, p.119-120.