“The church of the twenty-first century faces many crises. One of the most serious is the crisis of preaching. Widely diverse philosophies of preaching vie for acceptance among contemporary clergy. Some see the sermon as a fireside chat; others, as a stimulus for psychological health; still others, as a commentary on contemporary politics. But some still view the exposition of sacred Scripture as a necessary ingredient to the office of preaching. In light of these views, it is always helpful to go to the New Testament to seek or glean the method and message found in the biblical record of apostolic preaching.”
And this is just what R.C. Sproul does in his contribution to the current edition of Tabletalk magazine. “In the first instance, we must distinguish between two types of preaching. The first has been called kerygma; the second, didache. This distinction refers to the difference between proclamation (kerygma) and teaching or instruction (didache).” Having done this, and having looked to the preaching of the early church, Dr. Sproul asks: “What is appropriate for the transfer of apostolic principles of preaching to the contemporary church?”
You can read his answer in Preaching Christ.