Those who undergo severe austerities and penances not recommended in the scriptures, performing them out of pride, egotism, lust and attachment, who are impelled by passion and who torture their bodily organs as well as the Supersoul dwelling within are to be known as demons.
Even food of which all partake is of three kinds, according to the three modes of material nature. The same is true of sacrifices, austerities and charity. Listen, and I shall tell you of the distinctions of these.
Foods in the mode of goodness increase the duration of life, purify one's existence and give strength, health, happiness and satisfaction. Such nourishing foods are sweet, juicy, fattening and palatable. Foods that are too bitter, too sour, salty, pungent, dry and hot, are liked by people in the modes of passion. Such foods cause pain, distress, and disease. Food cooked more than three hours before being eaten, which is tasteless, stale, putrid, decomposed and unclean, is food liked by people in the mode of ignorance.
And that sacrifice performed in defiance of scriptural injunctions, in which no spiritual food is distributed, no hymns are chanted and no remunerations are made to the priests, and which is faithlessthat sacrifice is of the nature of ignorance.
The austerity of the body consists in this: worship of the Supreme Lord, the brāhmaṇas, the spiritual master, and superiors like the father and mother. Cleanliness, simplicity, celibacy and nonviolence are also austerities of the body.
From the beginning of creation, the three syllables-om tat sat-have been used to indicate the Supreme Absolute Truth [Brahman]. They were uttered by brāhmaṇas while chanting Vedic hymns and during sacrifices, for the satisfaction of the Supreme.
The Absolute Truth is the objective of devotional sacrifice, and it is indicated by the word sat. These works of sacrifice, of penance and of charity, true to the absolute nature, are performed to please the Supreme Person, O son of Pṛthā.
But sacrifices, austerities and charities performed without faith in the Supreme are nonpermanent, O son of Pṛthā, regardless of whatever rites are performed. They are called asat and are useless both in this life and the next.