I came across this quote today from Soren Kierkegaard:
Order the pastors to be silent on Sundays. What is there left? The essential things remain: their lives, the daily life with which the pastors preach. Would you, then, get the impression by watching them, that it was Christianity they were preaching?
Alongside was a comment by Jerome: A minister of Christ should have tongue, heart and hand agree.
Presently I am busy preparing a future preaching series, but these remind me of essential things before ever a word is spoken!