"Sweet is the melody, so hard to come by," according to songwriter Iris DeMent. Few of us can write music, and some (myself included) have trouble even carrying a tune. In any choir or congregation, it is easy to tell when someone is singing offkey. In the realm of the spirit it is more difficult. When a preacher has the words right, it is natural to assume that the "music" is there too, in the sense that the messenger's life and character authentically embody the truth of the message. Words, after all, are what the Christian gospel is all about, or so we are told. But every once in a while we hear someone about whom we have to say, "The words are theologically correct, but where is the melody?" Calvin Miller in his imaginative sketches The Singer and The Song has reminded us of the "music" of the Christian message, and nowhere is this music more evident than in John's vision of the redeemed on Mount Zion. What distinguishes these 144,000 from the rest of the human race is something very simple. They are able to learn a song (v. 3).