I love hymns. I love singing them and I love listening to them. Hearing the robust Cardiff Festival Choir belt out the stirring hymns of Ralph Vaughan Williams at what my wife regards as an intolerable volume is, for me, a terrific audio experience. It was only when I got to know certain Lutherans, though, that I began to think about hymns theologically. For classic Lutheran theology, hymns are a theological "source:" not up there with Scripture, of course, but ranking not-so-far below Luther's "Small Catechism." Hymns, in this tradition, are not liturgical filler. Hymns are distinct forms of confessing...