Jim Hamilton has a helpful little essay on his blog arguing that good preaching should "show your work." By this he means that you don't just tell people how to apply the text, you show them how you know it says what it says and how you reach the conclusions and applications you did.
What’s wrong with preaching where the work isn’t shown?
It’s too easy for preachers who don’t show their work to make assertions that the text of Scripture does not make, and this is complicated when they make applications from their own assertions. If you can’t show it to me from the Scriptures, it does not carry the authority of the word of God. In such a case, it is not the word of God that is being preached.
As I listen to preaching, I want to hear what the Bible teaches. I want the preacher to prove to me that what he’s claiming is what the Bible teaches. I want him to show me enough of his work to earn my trust, I want his applications to come from what the Bible actually teaches, and I would like to go away with a better understanding of the passage that has been preached.
I concur wholeheartedly that good preaching should show its work. This has always been my philosophy (theology really) of preaching. I have seen it modeled. I have seen its impact in church life and in my personal life. Granted preaching isn't a lecture but if preaching doesn't declare "this is what God's Word says" and at the same time show people that it clearly says that, the preaching can either (a) be hollow or (b) create a situation where people trust the preacher not the Word of God.
In response I left this comment over on Hamilton's blog:
We want our listeners to be able to be good Bereans to see if what we have said is in the word and how we know that it is in the word.
Good expository preaching doesn’t just tell people what the application is from a particular text but it models for people. It shows them how to see this is what the Word says and this is how it applies.
The pastor who mentored me has had a long term ministry of 25+ years in his church. When I went there fresh out of Bible college and seminary I found people in that church with no formal degree who were often better at studying the Bible, interpreting it and applying it than some of the people with whom I had graduated. It has always been a testimony to me of the powerful effects of “showing your work” in the pulpit.
Read Jim Hamilton's essay here.