I read a letter recently in my denominational newspaper that suggested that thematic preaching was the "junk food" of modern church life. By contrast, a healthy diet consists of good old expository preaching like we used to have. The problem is that the church has had centuries of good teaching, systematic theology and expository preaching and yet it remains largely ineffective when it comes to fulfilling it's primary mandate.
The letter writer went on to suggest that a "thematic" sermon was something that could be thrown together with some ease and without any real hard work or study. A few well chosen verses, a few hand-picked stories and or quotes gleaned from the Internet and the job was done.
But I happen to disagree with the premise that thematic preaching is to good teaching what a burger and fries is to a healthy diet. I know that a thematic sermon can, and should be, a carefully developed expository sermon too. I know that it takes as much, if not more, study and preparation to do a good job with a theme compared to a straight exposition.
And maybe the thing about a theme is that it forces you to think. It forces you to ask big questions of the text, and it forces to seek to hold together the whole message of the Bible and not just a small part. But then again that's probably true for the kind of expository preaching of which the letter writer spoke.
Perhaps, in the end, we need both. Perhaps the key to good preaching is making a connection between the Biblical world and the 21st century world. Between the world in which we live our day-to-day lives and the world of God's great revelation. Good old application as they used to say in my Bible study group.