When I hear this song and see the lyrics, I think of pyromania. I think, using the ideas that the other songs on this album tell stories of obsession, rape, and baptism, this is a baptism mof fire (to me). In the first verse, I think he's watching the fire he's just set, with someone who's wronged him burning inside. Especially with "Sift the ashes, stony things remain, I have left these things". I think his referrence to flame being Heaven-sent goes back to the Greek myth of Prometheus, bringing fire to man. He, in turn, was chained and suffers eternally. Anyways, just my rambling two cents.