From an interview with Graeme Goldsworthy, author of Preaching the Whole Bible as Christian Scripture:
Biblical theology shows us that all texts do not have the same relationship to the Christian believer. What happens when people are not shown this is a tendency to short circuit texts. In other words, evangelical piety can lead people to rush from reading a text straight into the question of what this says to us and about us. But, there is one mediator between God and man, the man Christ Jesus and biblcial theology helps us to see how Jesus mediates the meaning of any text to us. The Christian is defined by his or her relationship to Christ, not to any other person or event. Thus all persons and events in the Bible must stand in a discernible relationship to Christ if they are to say something about us.