Community in the New Testament sense of koinonia assumes and requires face-to-face communication, whether in a horse-and-buggy age or an Internet age. Three things marked New Testament Christian community: It was centered in Jesus Christ—believers met together as Jesus' followers, constituting his body; this fellowship was a gift of the Holy Spirit; and the community was missional. That is, the New Testament community was directed toward a purpose outside itself—actually being a living witness to Christ and the gospel's power in the world.

Many churches have a superficial idea (and experience) of community. Christian community is easily mistaken for mere cordiality, courtesy, or sociability. It easily becomes least-common-denominator "fellowship," not much different from the Kiwanis or a neighborhood potluck. Often so-called Christian community is marked by nothing that is specifically Christian and nothing that challenges the values of surrounding pagan society.

The question as posed, however, hints at the answer: The "one another" passages in the New Testament. Several things stand out when we look at the many "one anothers," such as "be devoted to one another" (Rom. 12:10), "serve one another" (Gal. 5:13), "carry one another's burdens" (Gal. 6:2).

First, most of these passages imply behaviors, not just attitudes. The New Testament writers are less concerned with how believers feel about each other than they are about their actions—their living together as community and publicly as disciples. Sometimes we reverse this, focusing on attitudes but forgetting action.

Second, all the "one another" passages imply a social context—appropriate structures in which these behaviors can be lived out. In the New Testament, of course, the ...