So firstly, I think there are two types of sermon where a preacher reasons from the Scriptures: expositional and topical.
a) An expositional sermon would be an exposition of the meaning of a particular text. The preacher starts looking at a passage of Scripture with no pre-conceived plan for what points he’s going to make. Instead he examines the text to see what it means, and his main sermon points are simply what he finds are the main points of the passage. We just read in 2 Timothy 3:16 that “all Scripture is breathed out by God and profitable for teaching”. So whatever passage a preacher turns to in the Bible, we know it’s been breathed out by God, and it’s profitable for teaching. So when a preacher says his text is (whatever it is), I’m looking forward to finding out what profitable teaching that passage teaches. So I’m really disappointed and frustrated when a preacher gives the impression he’s preaching on a particular text, but then preaches a sermon where only 1 of his 5 points is actually taught by that text.
b) A topical sermon is where the preacher decides what topic he’s going to preach on, and collects teaching on that topic from one or more texts of Scripture.
i) I’m not saying expositional sermons are always good and topical sermons are always bad, but if the preacher is going to preach on a topic, I still want him to at least show us the texts that support his main points so I can examine them, like the Bereans. It bothers me when a preacher says “the Bible very clear on this matter” but then doesn’t make any reference to any passage in the Bible that teaches such a thing.
I think what this comes down to is this: who or what do I trust to tell me the truth about God?
Do I trust the preacher? 2 Peter 2v1 says “But false prophets also arose among the people, just as there will be false teachers among you, who will secretly bring in destructive heresies”. Based on that, I would say no, I don’t unquestioningly trust the preacher, because there are some false teachers around.
Ok, next question: Do I trust myself to detect whether what a preacher says is true or not? Jeremiah 17v9 says “The heart is deceitful above all things”. So I would say no, I don’t trust myself to detect whether a preacher is telling the truth or not, because my heart can be deceitful.
So who or what do I trust? The Bible, because, as we’ve already seen in 2 Timothy 3:16, it’s been breathed out by God.
If I don’t trust the preacher to always teach perfect truth, and I don’t trust myself to detect when he’s not teaching perfect truth, I think the most reliable way for me to learn truth is for the preacher to clearly show me that he’s saying what the Bible says.
ii) Also, I do think there’s a risk with topical sermons, because if a preacher only ever gives topical sermons, it’s likely that he’ll preach on his favourite topics, and not preach “the whole counsel of God” as Paul did in Ephesus (Acts 20v27).
So although I wouldn’t say a topical sermon is always bad, I don’t think it’s a good idea to have them every week. And I think we should notice the difference between a sermon where the preacher has preached the meaning of a passage and a sermon where he’s preached on a topic. The fact that a preacher does a series of sermons where he takes “texts” from consecutive passages of Scripture doesn’t necessarily mean he’s doing an expositional series on that book of the Bible; he might just be taking words or phrases that appear in a those passages and preaching his thoughts on those topics.
It’s been kind of negative so far. I’m saying I want expositional sermons so I can see that the preacher is telling the truth because I can see he’s got it from the Bible, otherwise he might be subtly sneaking in false teaching. I hope you’ll see the following points as more positive reasons for wanting expositional preaching.