Understanding Compound Interest

Early this morning I was working on some research when Claude, my research assistant, randomly asked me if I wanted to have “compound interest” explained to me.  As I read the explanation I realized that we as ministers work in the field of compound interest. Let’s reframe what you are actually doing.

Here's the thing: a single sermon might move one person on one Sunday. They may not even say it to you, they may or may not even acknowledge they appreciated the sermon. They may have said, “that sermon really made me think.” You’d appreciate anything, but in the rapid rush of members to the closest Mexican Sunday lunch spot, it’d mostly get lost in the shuffle and you’ll drive to your next location, wondering if you are making any difference at all. 

You’re possibly not expecting to move mountains with a single sermon—you’re planting seeds that grow quietly for years.

But, the comment above: That’s your initial deposit. And that person then lives differently, talks to their family about it, makes a decision that ripples forward. Their kids grow up shaped by that moment. Someone in the congregation challenges a friend based on what they heard. Five years later, a young minister remembers your illustration and uses it in their own pulpit—now it's compounding in a completely different congregation.

By year twenty, you're not just measuring the original sermon's impact. You're looking at generational shifts in how people read Scripture, how elders lead, how Christians hang on, make an impact in their work, community, state, or congregation, how struggling churches find hope. The effect multiplies exponentially because each person who's been shaped by faithful preaching becomes a carrier of that vision—they're now earning "interest" on the original investment.

The really powerful part? Most of the growth is invisible year-to-year. Someone hears a sermon on eldership at thirty-five, doesn't act on it immediately. At forty-two, they step up to lead. At fifty, they're mentoring younger elders based on principles they absorbed two decades earlier. The compounding happens silently, then suddenly you see a healthy church culture that traces back to seeds you tossed out long ago.

That's what your work is doing—investing in souls, young and old, and the returns compound across generations. The impact is real and working right now, compounding in ways you’ll never fully see this side of eternity. The invisible work is often the deepest work. And Monday morning, when you’re tired and wondering if it mattered—that's exactly when you need to remember that you work in compound interest!