Srimad Bhagavatam Canto 11, Chapter 07, Text 45

SB 11.7.45

tejasvi tapasa dipto
sarva-bhaksyo ’pi yuktatma
 nadatte malam agni-vat
Saintly persons become powerful by execution of austerities. Their consciousness is unshakable because they do not try to enjoy anything within the material world. Such naturally liberated sages accept foodstuffs that are offered to them by destiny, and if by chance they happen to eat contaminated food, they are not affected, just like fire, which burns up contaminated substances that are offered to it.
The word udara-bhajana indicates that a saintly person eats only to keep body and soul together and not for sense gratification. One should eat palatable foodstuffs to maintain one’s mind in a cheerful mood; however, one should not eat luxuriously, because this will cause sex desire and laziness. A saintly person is always a perfect gentleman and is never greedy or lusty. Although maya tries to defeat him by offering different material allurements, ultimately these attractive material features are themselves defeated by the spiritual power of a saintly person. Thus, one should never disrespect a spiritually advanced personality but should worship him reverentially. To carelessly approach a Krsna conscious personality is just like carelessly approaching fire, which immediately burns if not handled properly. The Lord does not excuse mistreatment of a pure devotee.
Srimad Bhagavatam Canto 11, Chapter 07, Text 44
Srimad Bhagavatam Canto 11, Chapter 07, Text 46