Thought I'd let you peek into my sermon prep a little in case you were curious. My constant struggle (a good one of course) is where to bracket the sermon text from the Biblical narrative. Sometimes the text is easy to discern- Psalm 23 doesn't spill over into Psalm 24, but other times a judgment call has to be made. I've got to decide which verse to end on. Since I preach through books of the Bible and not randomly through topics I at least know where I am beginning each week but ending is another matter.
Take for example my sermon this week compared to the last two weeks. In Matthew 21:23 there begins a series of confrontations between the temple priests (especially the Pharisees) and Jesus. They question Jesus' authority and He responds with three parables that illustrate salvation history and the condemnation of unbelieving Israel- represented by those priests. After the second parable Jesus proclaims that He is the cornerstone on which a glorious eternal kingdom is being built (not limited to ethnic Israel). The third parable follows in Matthew 22 describing who is part of this kingdom and who is not. Then in Matthew 22:15 those priests come back at Jesus' three parables with three questions meant to trap Jesus and find cause to kill Him. He masterfully responds and silences His enemies proving yet again His divine authority and messianic fulfillment. In answering these questions Jesus also distinguished some characteristics of those who are citizens of this new and glorious kingdom.
So part of me sees these texts and observes about eleven or twelve potential sermons yet I am preaching all these verses in three sermons. What is my thought process in this? I believe there is great benefit in meditating slowly on the details of the text just as a microscope helps you see things in soil that you couldn't see by flying over that soil in an airplane. On the flip side there is also great benefit in seeing how all these texts flow together and connect in a greater narrative just as you would see things from an airplane that you couldn't appreciate up close and through a microscope. In preaching there should be balance. If you are in my flock I hope you are studying these texts (since I provide them ahead of time) "through a microscope" on your own and with other believers, so that when we come together on Sunday you can see the big picture as well.
This "high altitude" approach is not my favorite. I like getting down in the details and it kills me that I cannot preach four hour sermons to cover more in one Sunday! However I try to vacilate between styles and when we get to Galatians in 2011 Lord willing we will be more microscopic (so you'll have to read the whole book each week to keep the big picture in mind). The great comfort to me is that "all Scripture is God-breathed" and I cannot go wrong as long as I'm committed to faithfully expositing the sacred text as God intends it to be understood.