Kṛṣṇa explains why extreme, unauthorized penance is wrong: it is an act of violence. Those foolish people torture the material elements of their own bodies and, in doing so, they also torture the Supersoul (Kṛṣṇa) who lives within them. He labels such people as having a ‘demoniac resolve’ because they are acting against the Lord’s own presence. This verse provides a very healthy view of the body. The body is not a ‘trash can’ to be punished; it is a ‘temple’ that houses the Lord. Torturing the body through extreme fasts or self-mutilation is like being a bad landlord who allows the house to rot while the Guest is still inside. It shows a lack of respect for the Divine life-force. Real austerity should be ‘Sāttvikī’—balanced and nourishing. It teaches us to treat our physical and mental health as a sacred trust. We should discipline the body to make it a better tool for service, not destroy it out of a misplaced sense of ‘holiness’. By being kind to ourselves, we are actually being kind to the Lord within. We must avoid any ‘spiritual’ practice that is based on hatred of the physical world.