The distinctive characteristic of expository preaching is its instructional function. An explanation of the details of a given text imparts information that is otherwise unavailable to the average untrained parishioner and provides him with a foundation for Christian growth and service. The importance and centrality of thorough exegesis in preparing the expositor for this service cannot be overstated. Exegesis must itself be on a solid footing and must lead to development in supplementary fields that, in turn, provide important data for expository preaching, too. With the raw material of sermon preparation thus obtained, common-sense principles must be applied in putting the material into a form that the congregation can receive with ease and learn from.