I walked into the Santa Fe restaurant at 6:35 Wednesday morning looking forward to breakfast with friends. Gordon, Bob, Ron, and John were already seated around the table by the window. They were laughing about how I'd only order orange juice and then eat the bacon and hash browns off Gordon's plate. I grinned and slipped comfortably into my chair thinking, This is a close-knit group.

What makes a group close? It's a crucial question for Christians. Others can afford to see closeness as a luxury-a nice add-on, but secondary to the main task at hand. For the church, however, intimacy isn't an option. Jesus commanded his followers to love one another. Call it what you will-closeness, fellowship, cohesiveness, koinonia-that's what the family of God is about. But it's easier to extol the virtues of fellowship than to clarify what it is.

Justice Potter Stewart once said of pornography, "I don't know how to define it, but I know it when I see it." That vague legal standard hasn't proven particularly ...