Preachers face temptations to go anthropocentric at Christmas. There are lots of angles you can take with the Christmas story, but there are also lots of ways to be a little to creative. That can get us into trouble.I'm thinking of a Christmas message on marriage. The sermon went something like this: Mary and Joseph faced marriage stress due to an unplanned pregnancy; our marriages face stress too. Mary and Joseph could have blamed each other in lots of different ways; so could we. Mary and Joseph instead responded in faith and trust, and so can we when our marriages run into problems.The big question, I guess, is this: Is the story of Mary and Joseph in the Bible there to teach us about marriage? The minute we depart from the author's purpose (and, by extension, the Spirit's purpose) for the text, we're missing the point. We are also forced to be selective with the text and skip parts like the angelic visitation and the virgin birth.Two of the most important questions we can ask in keeping sermons theocentric are, "What is the purpose of the text?" And, "How can I preach a sermon consistent with that purpose?"Coming up: one more way not to preach at Christmas, and some excerpts from Kevin Vanhoozer's excellent book The Drama of Doctrine.