The story of Jesus and the rich man, presented variously in all three synoptic traditions, is notoriously challenging and has elicited any number of creative approaches to ameliorating what seems to most of us a ridiculously extreme demand.
From concocting a mythic entrance to Jerusalem that required a camel to unburden itself of all it was carrying to reading it as an intentionally impossible demand to drive us to Christ, interpreters over the centuries have been tempted to tone down this passage.
Which means we should read with care. Toward this end, I'd suggest attending to two elements of the text that will help us read and preach it with equal measures of integrity and creativity. The first is details. An author cannot tell us everything and the choices he or she therefore necessarily makes are clues to the narrative intention of a particular passage. While there are many revealing details in this passage, I will focus briefly on five.
In addition to paying attention to details, we also gain by exploring the gaps of any passage we are reading. Gaps are the elements of the story not told, the places we are invited to use our imagination and in this way enter into the story, even become invested in it. Gaps, therefore, invite questions that, depending on how we answer them, greatly shape our reading. I'll name what I think are four such gaps, both offering some possibilities for exploring them while leaving them open for you to enter into in relation to your preaching context.
Any and all of these questions have a variety of possible answers, and how we both address and employ them will be shaped by our sense of the particular situation and needs of our context. One thing seems clear. This passage is about wealth and the challenges it presents and, simultaneously, it is about discipleship, the need to follow Jesus and to be aware and even concerned about those things that would keep us from following Jesus "on the way."