Greg Heisler, author of the book, Spirit-Led Preaching (Broadman & Holman, 2007), draws this apt analogy about the relationship between the preacher's holiness and his or her effectiveness in preaching:
"On a recent stop at the gas station, a sign by the pump caught my eye. The sign read: ?Warning! To avoid risk, only pump gas into preapproved containers.' I know the sign was basically telling me that not everything is fit for holding gas, and it should be stored in the proper container.