By the time you show up to deliver a sermon out of the passage, you've invested many hours in the process.
The most important thing to recognize is that it was during the sermon creation process that you sorted through the tension, ambiguity, and complexity, and emerged with clarity. The people who are present, most likely, have not.
Therefore you must always remind yourself that most of the people listening to the message are hearing that passage for the first time that week - or the first time in their lives. They haven't invested the hours or the effort that you have when you stand up to speak, so logically they are not nearly as excited as you are about the conclusions you've reached!
If you don't engage the listeners, your words will be heard with their ears but not with their minds and hearts.
How do you engage people?
Provoking tension is the key to getting and keeping people engaged.
George Lowenstein, a behavioral economist at Carnegie Mellon University teaches that gaps in our knowledge cause pain. When we want to know something but don't, it's like having a rock in our shoe: we can go on if we want to, but we're aware that something needs to happen to resolve the situation.
Eugene Lowry connects this insight to preaching in his book The Homiletical Plot. He says, "The first step in the presented sermon, then, is to upset the equilibrium of the listeners, and is analogous to the opening scene of a play or movie in which some kind of conflict or tension is introduced....The central task of any sermon, therefore, is the resolution of that particular central ambiguity" (p. 31).
How do you provoke tension?
1) Question Conventional Wisdom
Everyone lives by a set of rules, whether we call them that or "guidelines, "principles," or something else, is beside the point. With every action we take, we have a corresponding expectation for what the result should look like. When the result matches the action, time and time again, we begin to think in formulas. For instance, x + y = z. Conventional Wisdom is comprised of hundreds of formulas like these in all walks of life - from finances to relationships. That's fine as far it goes, but sometimes life throws us a curveball and we find that the old formula no longer makes sense of the present situation. Because real life is messy, I'm convinced that the number of outcomes that can be logically predicted by Conventional Wisdom is slim to none. You are in a position to point this out, and thus provoke tension. For instance, you could say something like, "What we thought was x is really not...it's actually j."
2) Acknowledge and Interact with the Conclusions of Others
We live in a time when information and sound bites are freely distributed. People are exposed to the conclusions of others on websites, television programs, and radio shows. You must acknowledge that, specifically on the topic at hand, other people hold viewpoints and conclusions different from your own. Not to do so is not only counterproductive, but comes across as evasive. It's counterproductive because you've lost the opportunity to create and relieve tension through offering a worthwhile critique; and it seems evasive (especially if another conclusion is well-known), because you have chosen not to mention the "elephant in the room." Explain to people your reasons for choosing the view you hold over-against the other views on offer.
So don't shy away from the tension. Provoke it. People will stay engaged because they want the tension resolved. And when people are involved in active listening with a purpose (relieving the tension), your sermon is sure to stick.
Elements of a STICKY Sermon - Scripture
Sticky Sermons: Evolution of "The Stickiness Factor"