The most spine-chilling picture I know of (as a preacher) is a 19th-century painting of a young girl asleep in a pew. It is entitled 'My Second Sermon'. It encapsulates the tragedy of preaching failure. How can we improve ?
We find exhortations in the Bible to 'preach the Word,' and to 'encourage others by sound doctrine,'. In an image-dominated culture we need to be reminded that the Word is more fundamental than appearance. By the word of God the visible creation came into existence and new creation comes about. The primacy of God's word is not to be set aside.
So, what makes a good sermon? There is a mystery about real preaching, for in it God speaks. But we must not make it so much of a mystery as to mystify ourselves into despair. Let me suggest that there are ten simple essentials which make up a worthwhile piece of expository preaching.