I've always thought the use of "I Saw the Light" was a clever use of this Gospel song as Johnny Cash indicates at the end that he probably would have confessed to his misdeeds, but his hypocritical blackmailing wife/partner doesn't seem to realize that the heart of her religion is the fact that people can change--thus her "hold" on him causes her death. Not sure ole Hank was a-thinking about St. Paul's conversion on the way to Damascus when he composed the song, but he may have been.