“I know I’m preaching to the choir now!”
Pastors will say this for a few reasons. First, they don’t want to sound patronizing: “I know you already know and agree with this!” Second, they’re feeling insecure about saying something that feels obvious, and they don’t want to seem “un-insightful.” So it has the effect, “Please don’t tune out! I know you’ve heard this before.” Third, they appropriately want the listeners to feel like insiders: “People like us believe and do things like this.”