Eleven… because these are not divinely inspired, but I hope they point in the general direction of wisdom.

1. Thou shalt not be uncertain about the burden of your message. Sermons run over when the preacher doesn’t know what the sermon is about. What is the thrust of the message? Can you summarise the message in 15 words or less? If not, then you’ve probably got a commentary not a sermon.
2. Thou shalt not be overly long in your introductions. This is a frequent flaw in many preachers: we take too long to really get started. I agree with the wisdom that suggests most intros should be a paragraph or two, tops. So cut down the details of that opening illustration. Don’t spend too long in recapping the book. If you’re taking 15 minutes on sermon-intros, don’t wonder where all your time is going!
3. Thou shalt not be overly repetitive. Since preaching is oral communication, it demands a degree of repetition. The congregation aren’t reading a book. They cannot return to that previous paragraph and revisit what was just said. Clear, compelling preaching will often re-iterate key ideas and phrases. The danger is in overdoing it. At some point repetition becomes tedious and starts to insult the intelligence of the congregation.
4. Thou shalt not go off piste (and if you do… factor that in). Some preacher’s manuscripts hardly resemble the sermon they preach. The glasses come off, the pulpit is departed and off they go. If this is part of our preaching DNA, then fair enough; but it is not conducive to timeliness. So if you are ‘prone to wander’ factor that extra 20 percent into your word count.
5. Thou shalt not ignore the clock. This can be all too easy, especially if (as in my church) the clock is on the side wall! If time is of the essence, consider putting your watch on the pulpit. Recently when I was under particular time-pressure I actually had a stop watch running in front of me. It helped.
6. Thou shalt not become besotted with one particular idea. This is a slightly controversial one, but a Bible teachers’ excitement about a textual discovery can cause them to camp on a particular idea. We especially need to be wary that it isn’t just a hobby horse we’re riding. Ten minutes of a sermon gallops away when we’re on the back of one of those!
7. Thou shalt not give all the detail (but a few “deep dives” are actually helpful). Some preachers love to say everything about everything. Worse, they feel they are not properly teaching the text unless they discuss, quite exhaustively, every phrase and word. But let’s be clear about this. Even if we preached for an hour, we would only scratch the surface of any text. That being said, I would personally recommend a few “deep dives” here and there in every sermon. Why not pick two or three things in the sermon that you’ll go into more detail about? Detail makes a sermon engaging.
8. Thou shalt not do subpoints.
9. Thou shalt not neglect the practice of summarising. This is the key to preaching more briefly. Learn the art of summing up and speaking in broader strokes.
10. Thou shalt not be overly wordy. This is similar to the previous point but here I am emphasising the discipline of reducing the number of words we use in sentences. I’m reminded of the counsel of JC Ryle who said “preach as though you have asthma.” Ie. keep the sentences short.
11. Thou shalt not fail to land the sermon on the first attempt. This is not an encouragement to rush the ending. Not a few sermons suffer from the jolt of an unexpected landing. When we ‘bring the sermon in’, there should be a moderately paced descent, followed by a definitive landing. If knowing how we’ll begin is vital, perhaps as important is knowing how we’ll conclude. Be it with a poigniant question, a powerful story, or a penetrating last line, know where you’re setting things down.