Worshippers who can sing (or try to) don’t want their faith taken for granted. They long for melodic turns of phrase and memorable cadences. They’d be listening in the pews if they hadn’t needed to make music of empty air. Any tone-deaf preacher had better do his damnedest as an off-the-beat, white-throaty, black-robed, timorous, sharp, flat soloist for critically minded singers sitting there behind him, flinching at his droning and trying to forgive him for conducting only himself and turning his back on them.