I just heard this on the local NPR station. Lyrics were about the opening of the seven seals and in the chorus, the singer sings "I'm the Revelator, I'm the Apostle John." And no, the song was not John the Revelator. The singer was pretty gruff, on a level with Tom Waits but I don't think it was him. I did lyrics searches on Google and found only a dozen versions of "John the Revelator".