When my wife and I left a traditional church to plant a church by living as missionaries in a new city, we had no idea how deeply embedded we were in the Christian bubble. By "Christian bubble" I mean the subculture Christians create that allows us to conduct our entire life having minimal contact with anything "secular."

Bubble residents choose their activities based on where they can be with other Christians—from small groups, to play dates, to basketball leagues. The "world" is viewed as something to be avoided. We learned the Christian bubble can quickly envelop almost every aspect of life.

Taking a missionary posture with our church plant, we began employing strategies to build relationships with non-Christians. We hung out in coffee shops, invited people to our house, and talked to our neighbors. That doesn't sound like a big deal, but it was a challenge. We had spent our entire lives doing Christian things with Christian people, and engaging ...