What kinds of sermons?

What kinds of sermons are recorded in the New Testament? How many of them, if any, follow the pattern of the modern expository sermon? If some or all of them are not expository, what are they? 

Peter on Pentecost, Act 2:14-40.
Peter’s sermon on the day of Pentecost is one of the most notable biblical sermons, outside those of Jesus Christ Himself. It is the longest in terms of actual content that is recorded. It is the first, with the possible exception of Peter’s address to the 120 disciples in Acts 1:15-22. In this sermon Peter accomplishes 2 or 3 functions. He explains the phenomena that occur, then directs their attention to the life, death and resurrection of Jesus Christ. He quotes and explains scripture to support the testimony of Jesus’s resurrection. Finally, Peter directly interacts with the question from the crowd interrupts, as well testifying of Jesus and exhorting the crowd “with many other words” that Luke did not record in the book of Acts.

Would Peter’s sermon be described as expository in the commonly accepted definition of the term? Only by stretching the definition to include Peter’s sermon can Peter’s sermon here be described as an expository sermon. Peter did not choose a text to expound, find his points in it or focus his thoughts around it. He did use scripture. First, he uses Joel in a “this is that” explanation rather than an exposition. Second, Psalms with exposition, but more as a “proof text” than as a text that stands as the foundation of an expositional sermon. I’m not sure what type of descriptor best describes Peter’s sermon – topical, maybe? I’m fairly certain it isn’t expository!

Did Peter “preach the word” on Pentecost?

Paul on Mars Hill, Acts 17:22-31.
Paul’s sermon at Mars Hill in Athens is another well-known and remembered sermon. It is an address to philosophers who gather to hear him explain more about Jesus Christ. No text of scripture is used, for exposition or otherwise (there certainly are allusions to scripture). Paul begins with a burden on his heart regarding the superstition of the Athenians, and bridges from that superstition to present the true God and preach Jesus Christ and Him crucified. While not quoting on explaining scripture, Paul does quote some of their own poets to show that they are so close and yet so far – almost grasping the truth yet stumbling around as one blind. He appears to have been interrupted when beginning to expound on the resurrection, though perhaps there is more said than is recorded. The session ends with some deriding Paul and some wanting to hear more.

Would Paul’s sermon be described as expository in the commonly accepted definition of the term? Certainly not. There is no text of scripture that serves as the foundation of the sermon, and therefore no exposition of said scripture. It most likely fall under a “topical” descriptor.

Did Paul “preach the word” on Mars Hill?

Conclusion
These are only two examples among many, and all the many should also be consulted and considered. But it is worthy of notice that two of the most memorable sermons of the books of Acts should not be described as expository sermons. This “lays the ax to the root of the tree” that expository sermons are the biblically mandated sermons.

In these and others, Peter and Paul are not just preaching sermons but they are “making scripture” as well. They spoke with a direct and immediate inspiration of a kind not available to the preacher today. This should not frighten us away from these examples. But it should give us pause and bring us to them in diligent consideration. To what extent can we follow the examples of sermons by immediate inspiration? If we cannot follow with direct and immediate inspiration, should we follow them at all? It is intriguing – if not much much more – that the Holy Spirit would directly inspire sermons that are not expository, if that is the kind of sermon mandated in the Scriptures.