Four kinds of debt are irredeemable – debt to father, debt to mother, debt to ácárya, and debt to Guru (divine debt).
(a) The only way to do
service to one’s father after his death is to help every male member of
the Universe to progress on the path of highest development.
(b) The only way to do
service to one’s mother after her death is to help every female member
of the Universe to progress on the path of highest development.
(c) The best service to the ácárya is to work for the comfort and benefit of one’s ácárya and his/her family.
(d) The best service to Guru is to work according to His wishes.
But however much service one renders, one will not redeem the four debts until Mokśa (Salvation) is attained.