I just finished a book called Spiritual Power for Your congregation: A guide to lay activity in the church. It was published in 1956. I have had it on my shelf since 1999, but had never read it so I thought I should. It wasn't sure what to expect, but it was actually quite good. It is certainly dated, so some of the book's advice is no longer as useful as it might have been in the 50's.
But here's the really interesting thing. Reading through this book made me think of another book on my shelf that I didn't think would be that good. It is a book on preaching called "Preaching with Power." But again, I found that it was actually a very good book. In fact, I've read it a couple times now. So I checked the date on the preaching book and noticed that it was also published in 1956 by Concordia Publishing House.
Both of these books are out of print. If you go to the Amazon.com link for the first one, you can actually find some used copies, but the preaching book is gone.
A couple things impressed me about these books. First, it's always interesting to see how little things change over time. Over the course of 50 years many things change, but more often the church is really struggling with the same things as ever. In both of these books the authors described current attitudes in our churches, our families, and our societies. They described our culture and society, and the affect that they have on our work as Christian congregations and preachers. And I thought to myself more than once, "He could be writing this today."
The other thing that impressed me is that both authors relied heavily on the power of the gospel to be the power in preaching and in a congregation. Preaching with power is preaching that is the Word of God. The preacher doesn't need to add something to make his preaching more powerful. Preaching with power is proclaiming the power of God through the Word of God, no more, no less. Lay activity in the church makes a congregation powerful when members are hearing the Word of God in their homes, when they are studying it with others in Bible Class/Sunday School, and especially when they are gathering around Word and Sacrament in the Divine Service.