I think that this song is so powerful that its scary. To me, its a song between a man and Jesus. The stanzas are the words of the man who is talking to Jesus. Asking him how he feels that he is a sinner and a monster. And Jesus replies, "I will teach you" and "I will love you". It's a cry out to all humans who feel that they always fall short of the glory of God, telling them that Jesus will be your savior no matter what!