Churches that survive and thrive in a post-Christian world will be diverse in form, but will have this in common: they will be crystal clear about what matters, and what doesn't.
So what do we need?
I want to suggest that the first thing we need is people. That's not as trivial and obvious an answer as it might seem. Part of the problem with churches is that they act like they don't need people. They don't seem to care that people are dropping out and drifting away in droves, as long as they can keep other things that they think are more important. If you gave them the choice of either getting people back, or keeping the things they think are most important, people will lose every time. Try suggesting that the service time be changed to be more accomodating, and you'll see what I mean. Oh, it's nice if people come -- but come on our terms, and accept what we have to offer.
The truth is that you can't have a church without people. But that's only part of the answer. It's not exactly true that the church hasn't cared about people. But sometimes it has cared in the wrong way. We like to count people. Almost the first question people ask me when they find out I'm a minister is "How big is your church?" Meaning, how many people show up on Sunday. The second question is "Do you have many youth and young families?" Numbers matter.
But the church has never been about simply attracting numbers of people. It's who those people are -- or more, whose those people are -- that matters. The church of the 21st century will have to be in the business not only of attracting people, but of forming them so that they bear more and more of a family resemblance to Jesus who is Lord of the church.
So, if we want to get first things first, this is maybe the first of all. What the church really needs is people who know Jesus, who are willing to follow Jesus, and who are willing to point to Jesus by the way they live.