Thevasam constitute ‘a debt of the dead’ which ought to be repaid assuming the dead ones as being alive and living with us. During this period called pitru paksha, the lord of death, Yama raja enables all who shed their mortal frames to come back to earth and receive offerings from their descendants. For ages, it has been associated with such offerings being made to the dead christened pretas (spirits) and pitrus (forfathers).
It is believed that one owes three main debts. First its Devarina (debt to the gods), second is Rishi rina (debt to the guru) and the last but, not the least is the Pitru rina (debt to the forefathers). It is ordained that one must pay off these debts with utmost humility and respect.