Preaching is an odd task. I'm expected to deliver 60-70 sermons a year averaging around 15 minutes. Each year I deliver 15+ hours of memorized material that's different every week. I study and research. I pray about what to say. I write 1300 words give or take. I re-write, practice, polish, memorize, deliver, and repeat.
In today's world there are a lot of jobs that require public speaking, but few professions ask as much as the role of pastor when it comes to public speaking. Other professions probably have a similar amount of time of public speaking, maybe even quite a bit more, but probably not the level of variety of speeches. A lot of public speaking professions involve giving the same talk, speech, or presentation several times. Pastors aren't in the habit of recycling sermons. Well, they certainly shouldn't be. That's just lazy.
Stand up comedians, for example, spend much more time in front of audiences, but typically they use the same set with little tweaks here and there for several months in a row. They're always testing new material and honing their set so that the performance in Akron on Tuesday can be better than the performance in Indianapolis was on Monday.
Pastors don't often have such opportunity. I have one service. One shot. There's no honing a sermon once it is delivered. Pastors with multiple services get that chance, but they typically don't have time to think about what to change. Between the sermon at 8:00 and the sermon at 10:30, there's Bible study, no down time to re-write and consult with others on what to change.
Then there's the added pressure of this public speaking having the weight of being God's Word to the hearers. The pressure of finding the appropriate dynamics of Law and Gospel, the pressure of finding examples of application that mean something to the hearers. The pressure of not straying from the text and its message, but allowing the text to guide my words and structure and tone.
The sermon in the worship service can look very different depending on who the preacher is. Some sermons are all about how how people should be living. Some are a history lesson and little else. Some lead the congregation to praise and singing. Some lead the congregation to despair because of how terrible they are. Some kill and make alive through the words of Law and Gospel. Some speak to the Gospel of Christ's forgiveness, given to us by His blood. Some speak to the Gospel of Christ's victory over death in resurrection. Some do a combination of these things.
In Luther's Small Catechism, as he writes about the third article of the Apostles' Creed, Luther says the following:
I believe that I cannot by my own reason or strength believe in my Lord Jesus Christ or come to Him, but the Holy Spirit has called me by the Gospel, enlightened me with His gifts, sanctified, and kept me in the one true faith, just as He calls, gathers, enlightens, sanctifies the whole Christian church on earth and keeps it with Jesus Christ in the one true faith.
The work of preaching is the work of the Holy Spirit. The Holy Spirit inspired the Scripture each sermon is based upon and the Holy Spirit works where and when He will to guide preachers in their preaching. Yes, preachers are sinners and we make mistakes that we are to blame for, not the Holy Spirit.
I believe every sermon should aspire to do the Holy Spirit's work that Luther talks about, to call, gather, enlighten, sanctify, and keep God's people. Some sermons will do one of these things. Some will do more than one, perhaps even all.
As preachers, most of us tend toward one of these as our default. Some love to enlighten with explanations and history lessons. Some love to call with the Gospel, hoping people who are struggling to believe or who have not yet believed in Jesus will do so. Some love to sanctify, to speak to how to live a holy life. Some love to keep, to preach a word of encouragement that will nourish God's people and keep them going in their walk of faith.
There are many factors that go into good preaching, but perhaps the most important is variety. There are dozens, perhaps hundreds of Gospel metaphors in the Scriptures. There are typically dozens, perhaps hundreds of different people in each congregation. Different metaphors hit home with different people. If the only word of Gospel you speak is that of forgiveness, you may never speak a meaningful word to the woman who is filled with shame after being abused by her husband for years. If the only Gospel you speak is victory over death in the resurrection, you may never connect to that adulterer who is racked with guilt.
Ultimately, the sermon is the time for God's Word to come to His people filtered through and applied by the Holy Spirit working in the preacher. Sometimes the preacher filters and applies poorly or wrongly, but I find oftentimes that even when I feel like a sermon has failed, the Holy Spirit is constantly at work in the minds and hearts of the hearers to distract them from my mediocre words and implanting His own Word of Law and Gospel on the hearts of my hearers.