In addition to being an itinerant preacher, I also work as a high school math teacher. This year I'm teaching (for the first time) a Pre-Algebra course for middle school students. One of the things I've been doing with them as an "enrichment activity" is to play my sum-and-product game. In the sum and product game, I say, "I'm thinking of two numbers that add to ____ and multiply to ____." The students' job is to find the two numbers. For example, if I say I want two numbers that add to 14 and multiply to 48, the students will answer "six and eight."
Why am I doing this with my students? There's nothing in the Pre-Algebra curriculum that suggests this would be a good activity to spend time on. But because I'm an algebra teacher, I know that this ability is going to be very valuable to my students next year when they start learning factoring. (How do you factor x^2 + 14x + 48? It factors into (x + 6)(x + 8) - notice how my sum-and-product game is embedded in that solution!)
So here is an important principle that I have learned over my years of teaching: if you want to be a good teacher, you need to know your material more deeply than your students are ready to handle. Imagine if I tried to teach factoring to those middle school students - there is no way they are ready to comprehend that! But because I know the material deeply, I'm able to give them what they do need right now to prepare them for what comes next. To be a good Pre-Algebra teacher, I need to understand Algebra. To be a good Algebra One teacher, I need to have a good understanding of Algebra Two. I need to always have pushed myself further than I expect my students to understand.
The same is true in my teaching of scripture. When I am preaching, I spend a lot of time researching word meanings, word origins, commentaries, cross references to other parts of the Bible, cultural context, and more. But when I preach, most of that work stays in the background. If I taught the congregation everything that I had studied, everyone's lunches would be burned to a crisp by the time they got home from church! And I probably would not have accomplished a lot in the process.
As I do with my math classes, I take the things I know, the things I've studied, and I pare them down to the essence, peeling away all the layers of things that might have been interesting to me, but will probably not benefit my students. Sometimes that requires a bit of hard-heartedness to take some things that I have learned and know, and trim them out of my sermon.
But it's not wasted effort to have spent all that time preparing; it was of value to me, and it helped to carefully inform and shape my teaching.
One of the important end goals for me is that my messages will be emminently understandable. I don't care about sounding scholarly in my presentation. I don't care about sounding academic. I don't care about having people think that I "know a lot." I care about whether or not they understand what I'm saying.
One time after I finished preaching at a church, I was visiting with one of the elderly ladies of the church. She is one of the matriarchs of the church at 90-something years of age, and has been attending the same church for her entire life. She said to me (and remember, this is someone who has spent her entire life in church), "I like it when you come to our church. When you preach, you make it so I can understand what the Bible says."
That's a life-long churchgoer who has sat through at least ninety years worth of sermons. If she needs it taught simply, don't we all?