The most I could gain from this is that Sunday's slave is the church, and the song shows the possible greed and selfishness of certain church powers. The narrator works himself into a grave just for the church to bury him and forget. All the other days are left poor and starving, and these days are the non-religious. The bastard master is clearly God in this interpretation, but don't call him that to the church or they'll get mad, and if you whisper his name the church will try their hardest to convert you.
The most I could gain from this is that Sunday's slave is the church, and the song shows the possible greed and selfishness of certain church powers. The narrator works himself into a grave just for the church to bury him and forget. All the other days are left poor and starving, and these days are the non-religious. The bastard master is clearly God in this interpretation, but don't call him that to the church or they'll get mad, and if you whisper his name the church will try their hardest to convert you.