“Walter Wilson, a medical doctor and pastor/teacher in Kansas City, worked hard and wrote much to help preachers on this subject. In a series of lectures that he delivered in Chicago¬† many years ago, he astonished the group by stating that one hour of abandoned preaching was equal to eight hours at the executive desk and twelve to fourteen hours of manual labor. As a doctor he sustained these statistics with tests that he conducted on preachers of all ages and sizes. His text for that series of lectures was taken from those words in the Gospels, where Jesus declared, ‘I perceive that virtue has gone out of me‘ (Luke 8:46, KJV, emphasis ours).” (Stephen F. Olford, Anointed Expository Preaching, p.56)