truth can be fuzzy
"...we can’t know what the kingdom of God is by subtracting everything it has in common with anything else in order to determine what makes it unique, nor can we really know what the kingdom is by reducing it to some basic elements. Rather, we need to hear all the various ways in which the kingdom is described, all the images that the Bible uses to depict it, and so forth. The more we hear, the more we say, “Yes! The kingdom is like that, too.”There is a nice post over at Biblical Horizons that gets at the things we want scripture to do for us, but doesn't. It's a discussion of how scripture does not clearly define everything we want it to and in fact, there are subjects which it might never settle for us. This means we need a robust biblical theology to reason through those grey areas, as scripture itself is not self pronouncing. Anyways, don't let the long quote at the beginning of the article put you off; it's a sensible, engaging post. it is a nice brush with the limits of interpretation.
And while you're there, check out the little story about How Mark Came to Be Written - where he makes a case for the Gospel of Mark in a little story. Fun stuff!