Although the title for The Five Theological Orations has “no basis in the manuscript tradition”, as Lionel Wickham points out, there are good reasons to read these five as a unified sermon series. One reason is that they have interlocking parts.
A good example of this occurs at the beginning of Oration 28, where Gregory summarizes what he said in Oration 27: “Last time we used theology to cleanse the theologian. We glanced at his character, his audience, the occasion and range of his theorizing.” In these two sentences, Gregory connects the two sermons.
It’s also worth noticing that in these sentences, Gregory summarizes his previous sermon in a better way than anything he said in the previous sermon. This observation gives us a tip for how to listen to sermons.
Here’s the secret: sometimes it takes a whole sermon plus some resting time for a preacher to figure out the best way to say what he needs to say, even master rhetoricians like Gregory. And so you’ll sometimes find the clearest expression of the preacher’s core message not in the conclusion of his sermon, but in the introduction to next week’s sermon. Just listen for the signal: “Last time we…”