As evangelicals, we take the Bible as our authority. And when we look at the Bible, we find that, actually, the second most common command is to sing. It wouldn’t come up that often if it weren’t extremely important to God. Yet when Kristyn and I started studying this, we realized we couldn’t find good books on singing for ordinary people.

In 2013, we did a series of leadership lunches where we would ask the participants: “What’s the first question you ask about music in church?” And we got a whole range of answers, from production to musical style to personality to presentation. But not one person asked, “How did the congregation sing?” And so we find ourselves in a peculiar culture where what is primary—singing—has become secondary, and what is secondary—all of these other concerns—has ...