A sermon is like a love affair—it's easier to start one than to end one.
The conclusion of the sermon is usually the hardest part of the sermon to prepare. However, it is also the most important part of the sermon. The lawyer knows that no matter how eloquently he argues his case, if his closing arguments don't draw forth a positive verdict, he fails. The salesman is well aware that no matter how fluent his sales presentation, if he doesn't know how to "close" so as to make a sale, he starves.
We preachers must learn the same lesson. It's important that the sermon introduction grasp the congregation's attention. It's important that the sermon body bring instruction and inspiration. But it's even more important that the sermon conclusion help listeners decide what action they're going to take. We must "close" for Christ; we must concentrate on the verdict.
This most important part of the sermon is also the most neglected. Perhaps it's because we tend to run out of preparation time. Or perhaps we expect the heat of the moment to create the conclusion as we preach it. It is true that the Holy Spirit may cause us to change the conclusion somewhat as we preach, but I doubt that He often leads us to prepare it as we preach. The Spirit seldom over rides indolence.
No hard and fast rules
It's both dangerous and presumptuous to lay down hard and fast rules for preparing effective conclusions. In the first place, there's room here for individuality. Second, we must not bore our congregations by concluding the same way every time.
Watch the fisherman. If the fish don't bite on one bait, he tries another. Sometimes he uses a worm and some times a fly—it depends on where he's fishing and what he's trying to catch. He doesn't bait his hook with what he happens to like best or is most used to; rather, he uses whatever lands the most fish. We must be as wise in preparing sermon conclusions, varying our techniques when "catching" men and women for Christ.
There are, however, two basic parts that we should quite invariably include, and they should be in their right order. The first part of the conclusion should be a summary of the sermon. The last part ought to be a call to action.
Prepare a summary
If the basic sermon theme and divisions have been thought-provoking, repeating them constitutes a fair summary. But the ideal summary presents the sermon's basic thoughts in a new way; the congregation gets bored if we re-preach the sermon in the summary. The most interesting summary is a detailed example that illustrates the sermon's emphasis.
Don't present any new arguments in the conclusion. To do so is to go contrary to its purpose, which is to recapitulate and apply the arguments or ideas already given. Thus, you will generally need only a few sentences in the summary portion of the conclusion.
Solomon didn't have preaching directly in mind, but he gave excellent homiletical advice when he said, "Let us hear the conclusion of the whole matter" (Eccl. 12:13). Too many conclusions unintentionally summarize only the last portion of the sermon body. You can drive your point deeper home if your summary pulls together your whole sermon.
Let's liken the sermon to a landscape painting and each division of the sermon body to an object in the painting— the tree, the cloud, the road, the horizon. When you stand up to preach, you have the entire picture in mind. You begin, in word pictures, to paint it for your congregation. To you the picture seems so clear, so simple. Surely everybody must see it. But many don't. You are most fortunate if the majority see the separate parts—the tree, cloud, road, and horizon. In your summary, often for the first time, worshipers see how the individual parts of the sermon fit together. Only as you summarize do they see the full picture. And that's why a well-prepared summary is so essential!
Include a call to action
The sermon summary reviews and in forms. The call to action challenges each listener to act on that information. The summary instructs the mind. The call to action confronts the will. A discourse is not really a sermon at all unless it does both.
Ring Lardner, describing life in a certain expensive hotel, noted, "Everybody puts on their evening clothes like some thing was going to happen, but it don't." Too many worship services, too many sermons, put on all the external trap pings as though something was really going to happen—but it doesn't.
Let's always preach so that people will not only believe something—let's preach so that when they believe, they will do something. Let's always call for action!