Mahabharata Anushasna Parva Chapter 23:4

Mahabharata Anushasna Parva (Dana Dharma Parva) Chapter 23:4 The girdle of a Brahmana should be made of Munja grass. That for one belonging to the royal order should be a bowstring. The Vaisya's girdle should be made of the Valwaji grass. Even this is what has been laid down in the scriptures. Listen now to me as I expound to thee what constitutes the merits and faults of both givers and recipients of gifts. A Brahmana becomes guilty of a dereliction of duty by uttering a falsehood. Such an act on his part is sinful. A Kshatriya incurs four times and a Vaisya eight times the sin that a Brahmana incurs by uttering a falsehood. A Brahmana should not eat elsewhere, having been previously invited by a Brahmana. By eating at the house of the person whose invitation has been posterior in point of time, he becomes inferior and even incurs the sin that attaches to the slaughter of an animal on occasions other than those of sacrifices. So also, if he eats elsewhere after having been invited by a person of the royal order or a Vaisya, he falls away from his position and incurs half the sin that attaches to the slaughter of an animal on occasions other than those of sacrifices. That Brahmana, O king, who eats on occasions of such rites as are performed in honour of the deities or the Pitris by Brahmanas and Kshatriyas and Vaisyas, without having performed his ablutions, incurs the sin of uttering an untruth for a cow. That Brahmana, O king, who eats on occasions of similar rites performed by persons belonging to the three higher orders, at a time when he is impure in consequence either of a birth or a death among his cognates, through temptation, knowing well that he is impure incurs the same sin. He who lives upon wealth obtained under false pretences like that of sojourns to sacred places or who solicits the giver for wealth pretending that he would spend it in religious acts, incurs, O monarch, the sin of uttering a falsehood. That person, belonging to any of the three higher orders, O Yudhishthira, who at Sraddhas and on other occasions distributes food with the aid of Mantras, unto such Brahmanas as do not study the Vedas and as are not observant of vows, or as have not purified their conduct, certainly incurs sin." "'Yudhishthira said,—"I desire, O grandsire, to know by giving unto whom the things dedicated to the deities and the Pitris, one may earn the amplest rewards." "'Bhishma said,—"Do thou, Yudhishthira, feed those Brahmanas whose spouses reverently wait for the remnants of the dishes of their husbands like tillers of the soil waiting in reverence for timely showers of rain. One earns great merit by making gifts unto those Brahmanas that are always observant of pure conduct, O king, that are emaciated through abstention from all luxuries and even full meals, that are devoted to the observances of such vows as lead to the emaciation of the body, and that approach givers with the desire of obtaining gifts.