Bhagavatapurana 4.22.46

46. It is the Brahmin who eats his own (bread), wears his own (clothing) and gives his own (property); (while) the Kshatriya and others merely eat his food simply through his kindness, (therefore they have no right to make gifts).

47. May those, who, possessed of conclusive insight into Vedas and abounding in mercy, have, in their discourse on Atman shed on us such true light of the Almighty Lord, be ever pleased with their own deeds! Who is it that could do them anything in return, except by joining his own hands (in supplication), (or), and become an object of ridicule?