This spread came to me in a dream last night. I think it will go in the Tarot Architect (current working title), which is a future book about tarot spreads I've created over the years. The Sermon Spread is a classic three-card layout, which is based on one aspect of the Hierophant's archetype: the Preacher.
In my experience, nobody really likes to be preached at - unless we happen to be in a sermon. Or lectured at, unless we're attending a lecture. And yet, I think most of us do this at some point in our lives. And most of us can probably think of someone we know, who just loves to preach; it's a habit. Preaching is one of the aspects - thankfully not the only one - of the archetypal Hierophant, Major Arcana no. 5. The old card title is Il Papa, the Pope. The missionary mindset can be seen as a shadow side of the archetype - thinking based on "my way or the highway", that there's only one correct, right way of thinking or believing.
Here's the layout:
In the dream it was emphasised that both aspects are equally important, and should be included in the interpretation: internal and external. I really like that. At the heart of this spread is, of course, the magic keyword communication. How and what we speak to others and ourselves. At least in the colloquial meaning "preaching" usually implies repetition: someone who keeps banging on and on about something. If we keep preaching at ourselves something, whatever it is and however conscious or not we are about it, there's a good chance we might end up believing it. To quote Rachel Pollack, "Safety comes through repetition." And if we do it to others, there's a good chance they will get bored.
I can see this spread as an introduction to Shadow work, which is a Jungian term, referring to a practice of making the unconscious conscious. It usually implies unearthing especially those aspects or sides of ourselves, which we would rather avoid facing. Sometimes the Shadow (archetype) can also be about positive traits in oneself, which one refuses to see.
In case you decide to try this spread, I'd be interested to hear how it went.