There is a tale that goes along the lines of:
On the first Sunday, a new vicar used John 13:34-35 as the sermon text. “A new command I give you: Love one another. As I have loved you, so you must love one another. By this everyone will know that you are my disciples, if you love one another.” The congregation was pleased with the vicar’s first Sunday and first sermon.
The next Sunday they were surprised when their new vicar preached the exact same sermon using the exact same scripture lesson. When the vicar preached it a third time on the third Sunday, the congregation complained to the leadership. The chair of the vicar-parish relations committee went to the vicar and asked the obvious question, “Why are you preaching the same sermon every week? The vicar simply answered, “When the church starts practicing this sermon, I’ll write a new one!" 