It's amazing, really. While driving to the gym this morning, I actually listened to a sermon on the last twelve verses of Mark. The caveat? Before he started, the speaker make it clear that "these verses are not Scripture." For the life me, I don't know why anyone would preach on a text that isn't Scripture. I think it's fair to say that the speaker had a shallow grasp of the facts. He said that the best Greek manuscripts do not contain Mark 16:9-20. The truth is that only 3 Greek manuscripts (and only 2 of these are "early") end Mark 16 at verse 8. Over 1,600 Greek manuscripts (that's 99.9%) support the long ending of Mark. He then went on to say that the contents of Mark 16:9-20 differ dramatically from the rest of the Gospel -- an assertion that's been falsified over and over again by numerous scholars.
Anyway, if, in your mind, a passage in the Bible is not Scripture, then don't preach it. It's as simple as that.