One of the advantages of a pastor moving from church to church, or becoming an itinerant evangelist, is that he can preach the same message over and over again. Whereas, the pastor/teacher who stays for a long period of time with the same congregation must maintain a consistent diet of fresh expositional teaching.
We have a various interesting journal entry in the diary of Benjamin Franklin regarding the preaching of itinerant evangelist George Whitefield. Franklin was an unbeliever, but he considered Whitefield a friend. Read carefully this 1740 evaluation of Whitefield's preaching by Benjamin Franklin:
"He had a loud and clear voice, and articulated his words so perfectly that he might be heard and understood at a great distance, especially as his auditories observed the most perfect silence . . . By hearing him often, I came to distinguish easily between sermons newly composed and those which he had often preached in the course of his travels. His delivery of the latter was so improved by frequent repetition, that every accent, every emphasis, every modulation of the voice, was so perfectly well turned and well placed, that, without being interested in the subject, one could not help being pleased with the discourse."
(Cited in Edwin S. Gaustad, The Great Awakening in New England, p. 29).
One of the more difficult challenges for the preacher of the Word of God, even George Whitefield, is to give fresh, "newly composed" sermons with clarity, unction and power. Itinerant evangelism and easy listening messages have their place, but a round of applause should be given to those tenured pastors (i.e. Gill, Keach, Lloyd-Jones, MacArthur, Piper, etc.) who have made - or make it - a practice to expositionally teach the Word of God to the same congregation for decades.
In His Grace,