Most rock songs are about one of three things: Love, Drugs or, Love of Drugs. I think this song is a metphor for recovering from drug addiction. At the beginning of the song he is reflecting on how he felt when he was high and how he percieved that he was in control. "I useed to rule the world" The reference to pillars of salt pillars of sand is referring to the story of Sodom and Gomorrah. The singer is walking away from sin and even a brief look back will cause his complete downfall. He also talks about his friends not recognizing him. He is asking for his friends to reach out of their comfort zone to support him "be my mirror, my sword and shield..." The reference to St. Peter calling/not calling is the addict realizing that he must answer to a higher power.