Just read a great article explaining the three approaches to preaching known as …

The point was that just like CSI which keeps you guessing till the end, our sermons sometimes are best organized by sharing little details all leading up to a final point. This is called Inductive reasoning where the details are given leading up to a big idea.
And Just like 20/20 our sermons are best organized by stating the main point up front and then sharing the details. This is the deductive approach. When you hear a preacher give his main point at the beginning and then give supporting material which explains, illustrates and proves that point and then applies it, he is preaching deductively.
But when a preacher begins with details that lead up to a main point which is followed by more details supporting the point, this is a mixed approach, sort of like Law and Order which keeps you guessing till halfway through when they reveal who the bad guy is and then prove it.
Try this out and keep your audience guessing. The best time to use one of these is when the passage does. If it presents the main idea up front, then use that. When it leads up to it inductively, then use the inductive approach.