A couple of decades ago, churches split in a grand debate over worship. Contentious arguments raged over every aspect of worship style, components, decorum, and practically everything else. Every church seemed to be choosing between opposites—organ or praise band, historic liturgy or rock liturgies, contemporary songs or historic hymns. The fallout was ugly. Assemblies erupted in dissonance and members on the losing side transferred out.Years later, the voices have calmed and the dust has settled. Some pastors declared a sort of “separate peace” by establishing rival worship services—one traditional, one modern. Others went the “blended worship” route. While this...