Finishing a sermon is neither easy nor natural. There are plenty of ways to crash a good sermon: I’d like to offer a few I’ve observed in myself and others.
1. The "Searching for a Runway" Conclusion—This is a common one that we fall into when we fail to plan our conclusion before starting to preach. As the sermon wears on, we become aware of the need to land the plane but have to search for a decent runway on which to land it. Consequently, as we’re coming in to land, we remember that we haven’t reinforced a certain element of the message, so we pull out of the descent and circle around for another attempt. Next time in, we think of half of a conclusion that might work better and so pull out again, circle around and turn in to another possible landing strip. Needless to say, passengers don’t find this pursuit of a better runway to be particularly comfortable or helpful. When the message drags on a couple of minutes or ten longer than it feels like it should, any good done in the sermon tends to be undone rather quickly!
2. The "Just Stop" Conclusion—There are some preachers who don’t seem to be aware of the possibility of a strong finish and so don’t bother to land the plane. It simply drops out of the sky at a certain point. Once all has been said, without any particular effort to conclude the message, it's suddenly over. This is a particular danger for those who go on to announce a closing hymn, I find.
3. The "Overly Climactic" Conclusion—At the other extreme are those who know the potential of a good finale and so overly ramp up the climactic crescendo in the closing stages. After preaching a ho-hum message, they suddenly try to close it off with a fireworks display that will leave everyone stunned and standing open mouthed with barely an “ooo-aaah” on their lips. Truth is that if the message hasn’t laid the foundation for such an ending, then people will be left stunned and unsure of what to say, “Uuuugh?”
4. The "Uncomfortable Fade" Conclusion—Perhaps the domain of new, inexperienced and untrained preachers, this follows the general comfort rule of preaching: if you are not comfortable in your preaching, your listeners won’t be either. So the message comes to what might be a decent ending, then the speaker, well, sort of, just adds something like, “That’s all I wanted to say, I think, yeah, so...” (like this paragraph, 20 words too long!)
5. The "Discouraging Finale" Conclusion—Another tendency among some is to preach what might be a generally encouraging message but then undo that encouragement with a final discouraging comment. People need to be left encouraged to respond to the Word and to apply the Word, but some have a peculiar knack for finishing with a motivational fizzle comment.
6. The "Machine Gun" Finish—Wildly fire off a hundred different applications in the final minute in the hope of hitting something—no depth, very shallow, badly aimed, rarely hits the target and often has nothing to do with the passage.
7. The "Salvation by Works" Finish—After preaching the wonders of God’s grace in Jesus Christ—undermine that grace by throwing doubt on their own salvation because of their sin or not doing the application you suggest.
8. The "Left Field" Finish—Where the conclusion and/or application has very little to do with the passage, your sermon, or anything else.
9. The "Not Again" Finish—Where (for some funny reason) the conclusion is the same as every other conclusion you’ve given for the last three years—it also happens to be your hobby horse and is often one of pray more, give more, evangelize more, read the Bible more and come to church more.
10. The "Gospel out of Nowhere" Finish—Where the preacher feels the absence of the gospel in the message and so levers it in at the conclusion without any sense of connection to what has gone before. (To a thinking listener, this may feel a little forced and intellectually inconsistent.)
And while I'm at it, here's a bonus:
11. The "Tearjerker" Finish—Where the speaker seeks to cement emotional response by throwing in a random and largely disconnected tearjerker of a story (perhaps involving a child, an animal, a death or whatever). Strapped to this emotional bomb, the preacher hopes the truth of the message will strike home (even though in reality, the truth will probably be smothered in the disconnected emotion of the anecdote).