What is the Most Important Part of a Church Service?
Seems like an innocent enough question, but people usually use this question as a diagnostic test. If you answer "the Lord's Supper" the assumption is that you're Roman Catholic because all good Protestants should answer "the Sermon." In fact, still to this day, many Protestant churches do not celebrate the Lord's Supper every Sunday, so the sermon is a normal candidate for being the most important part.
But this question is really more about what Sunday worship is. Is it the kind of thing that has a center? Or is it the kind of thing that has a trajectory? I can see a certain logic in saying that the sermon is the center of the service. It is the time when we settle down and hear from God's word. And God's word is certainly central to the Christian life. So, if Sunday worship is a circle, then yes, it makes perfect sense to say that the sermon is the most central part. But if Sunday worship is a story that moves from calling, to repentance, to instruction, and then to peace with God as his table, it makes sense to say that the endpoint is the most important part.
Take Harry Potter, for instance. Is his duel with Voldemort the most important part of the story? I'm not sure about "most important part" but it is definitely the destination of the story - the endpoint. There still awaits a Sabbath rest for God's people and in the scriptures it is described as a "wedding feast of the lamb" - eating with Jesus. And so, as a microcosm of world history, Sunday worship has a very important endpoint - peace and rest in a meal. Back to Harry Potter again, there are many other important parts of the story that make the ending possible - that help it hold together and make sense. The sermon is like that. The endpoint of world history is made possible because God dwells powerfully in world history through his church and through his word. And so every Protestant should be able to lift his or her head high and not be ashamed of thinking very highly of the sermon. At the same time, let's not mistake the importance of the sermon as being some kind of endpoint. The first part of worship is not the pre-game ceremony for the sermon. If anything, the first parts of worship include the sermon; all of these lead to a foretaste of our future rest.
So the next time someone asks what the central part of Christian worship is, realize that another question is being begged - the assumption that a worship service has a "center" rather than a trajectory.