
Sunday worship at Calvary Foursquare Church in Silver Spring, Md., starts in an empty parking lot. The congregants usually arrive on foot with well-worn Bibles in hand. They come in groups, Latino mothers and toddlers, grandparents and friends. "Que Dios te bendiga"--May the Lord bless you--each one says, offering hugs and kisses to everyone they meet. They board a refurbished school bus painted with a Bible verse and the church's Spanish name: Iglesia Cuadrangular el Calvario. When it pulls out into the busy street, I hop in my car and follow. Twenty minutes later, the bus makes a sudden left into...