There is a reason why it’s important early on to clarify what your church sermon subject is. Doing so should ensure that you stay on topic as you then craft your Sunday sermons. I used the word “should” because I have worked with numbers of pastors who have told me what their sermon subject was, only to somehow forget this in the process of putting their thoughts together.
Look at Luke 14:12-14, where our Lord tells us that when we have guests we should invite people who can’t repay our kindness. Examples would be the poor, the blind, the lame, etc. So the subject is something like “Hospitality According to Jesus.”
Everything in the sermon series should relate to that overall theme. Even so, I have heard sermons on this passage that have gone in various directions, including the need to witness more about the faith and also spend more time reading the Scriptures. I have no idea how those themes made it into the sermon, but they did!
Again, there’s a purpose for making sure you know what your basic church sermon subject is. It’s to ensure that you not get off-track as you lay out where you are going with your message.
Ministers will sometimes object and tell me, “But I want to talk about two or maybe three subjects in my sermon.” I tell them they can talk about as many as they want as long as they stay to their listeners, “I am finished talking about ‘Hospitality According to Jesus,’ and now I want to talk about a different topic, which is ‘__________.’”
This way, at least their people understand what’s happening, and hopefully the preacher does as well!