Machine Head - Darkness Within Lyrics Meaning

This song is about the realotionship of robb flynn to music. Music means everything to him.I saw them last year on their eight plague tour and before they played that song robb flynn said, that it doesn't matter what other people think about you. You should be yourself and trust in music. Because music can express so much. And no matter what happen music will be around.
So that song is about a man who have lost faith in god. But then he found his faith in music and from that moment he felt save.