It is not difficult in such a world to get a person interested in the gospel; it is terrifically difficult to sustain the interest. Millions of people in our culture make decisions for Christ, but there is a dreadful attrition rate. Many claim to have been born again, but the evidence for mature Christian discipleship is slim. In our kind of culture anything, even news about God, can be sold if it is packaged freshly; but when it loses its novelty, it goes on the garbage heap. There is a great market for religous experience in our world; there is little enthusiasm for the patient acquisition of virtue, little inclination to sign up for a long apprenticeship in what earlier generations of Christinas called holiness. -Peterson "A Long Obedience in the Same Direction"

This is why I think it is helpful if pastors stay at one church for a long, long time.