This is an important question. After all, many people equate expository preaching with a verse-by-verse approach. But there are some differences. As I offer some counter points from a genuine expository perspective, please bear in mind that we may still take an apparently verse-by-verse approach at times in our preaching. Nonetheless, these thoughts need to be kept in mind:
1. Verse-by-verse preaching can flatten out inspired texts and fall into a running commentary approach. That is, a verse is an artificial division of the text. The real division is the natural unit of thought that the author was seeking to communicate. In a Psalm this might be the strophe, or the parallelism, not to mention the psalm as a whole. In an epistle it would be a paragraph. As preachers we need to communicate the thoughts intended by the author, which may not happen if we treat each verse as a unit of thought.
2. Verse-by-verse preaching can treat the text as a data source, rather than honouring its intended function. Following on from number 1 above, when verses are treated as micro-units, then there is a temptation to view the text as a collection of data to be mined for interesting snippets. This is very different than honouring every detail as part of the whole communication effort. Every detail matters, but we need to communicate the “distilled thought” of the whole unit, as opposed to selecting highlights from a flattened text.
3. Verse-by-verse preaching can lose sight of the inspired genre and form of a text. This may be restating the same thought from a different angle, but it is important. God didn’t just inspire the meaning of the text. We have to take the genre and form as vehicles in which that meaning is conveyed. Consequently we must read a poem as if it were a poem, and a section of discourse as exactly that. It does not help to preach a Psalm and a prophecy and a narrative and an epistle in the same way.
4. Verse-by-verse preaching can lose tension and emotion from a passage. Not only does it tend toward treating verses as data banks, it can also flatten the emotive force of a passage. There is often a tension to be felt, or a resolution to be experienced. Verse-by-verse preaching easily can lose sight of such realities.
Submitted via comment, thanks David: 5. Verse-by-verse preaching tends to reinforce the tendency of many believers to focus on “proof” or “key” verses, rather than learning the argument of the author. Context can be lost and, ultimately, verses come to mean something other than they were meant to.
Bottom line. For some preachers, a verse-by-verse approach would help increase their biblical content and focus. However, a strict verse-by-verse approach doesn’t inherently recognize that while every verse is fully inspired, not every verse is created equal.