The biblical narratives tend to be lean in their writing. What Luke could write in six, or ten, or twenty-six verses would take a contemporary writer three-hundred pages. Nevertheless, there are many details tied into the narratives.
There are interesting word choices – such as the word used for “have mercy on me” in Luke 18:9-14. There are significant passing remarks, like the fact that Mark tells us the grass was green at the feeding of the five thousand. There are key functions achieved by narratival details, like the angry grumbling of the crowd under the tree in Jericho when Jesus invited himself to Zac’s place. There are intriguing ways around saying the straight answer, like after the Good Samaritan, the questioner of Jesus can’t bring himself to say the word “Samaritan” in a positive sense. Or the elder brother in Luke 15 who won’t refer to the younger son as his brother. There are interesting repetitions, like “he believed” happening twice in twenty-four hours at the end of John 4. I could go on.
So what to do with such interesting “incidental” details?
One approach is to completely miss them and preach every story as if it is the same as several other stories. That could apply to a story recorded in several gospels, but sounding the same whatever passage you preach it from. Or it could apply to a particular story becoming a generic story-type that could be preached from numerous passages.
Another approach is to dismiss them and give some sort of sophisticated sounding explanation of how there is no reason for it to be here, but it shows the human-ness of the author. Certainly the author was a human, but often a dismissal of detail in Scripture is evidence of nothing more than the preacher’s lack of careful study and thought.
Another approach is to dissect them and preach a series of distinct messages based on separate textual triggers. In this approach the preacher goes off on a mini-logue about grumbling from the crowds at Zac’s tree, but fails to recognise the inherent thrust of that detail in that particular story. Often true truth will be preached from the wrong text.
Are there incidental details? Depends how you view and preach the text. I appreciate this quote from Flannery O’Connor:
“A story is a way to say something that can’t be said any other way, and it takes every word in the story to say what the meaning is.”