Mahabharata Anushasna Parva Chapter 115:3

Mahabharata Anushasna Parva (Dana Dharma Parva) Chapter 115:3 Those fierce persons who are engaged in slaughter of living creatures, never find protectors when they are in need. Such persons should always be molested and persecuted even as beasts of prey. Through cupidity or stupefaction of the understanding, for the sake of strength and energy, or through association with the sinful, the disposition manifests itself in men for sinning. That man who seeks to increase his own flesh by (eating) the flesh of others, has to live in this world in great anxiety and after death has to take birth in indifferent races and families. High Rishis devoted to the observance of vows and self-restraint have said that abstention from meat is worthy of every praise, productive of fame and Heaven, and a great propitiation by itself. This I heard in days of old, O son of Kunti, from Markandeya when that Rishi discoursed on the demerits of eating flesh. He who eats the flesh of animals that are desirous of living but that have been killed by either himself or others, incurs the sin that attaches to the slaughter for his act of cruelty. He who purchases flesh slays living creatures through his wealth. He who eats flesh slays living creatures through such act of eating. He who binds or seizes and actually kills living creatures is the slaughterer. Those are the three kinds of slaughter, each of these three acts being so. He who does not himself eat flesh but approves of an act of slaughter becomes stained with the sin of slaughter. By abstaining from meat and showing compassion to all creatures one becomes incapable of being molested by any creature, and acquires a long life, perfect health, and happiness. The merit that is acquired by a person by abstaining from meat, we have heard, is superior to that of one who makes presents of gold, of kine, and of land. One should never eat meat of animals not dedicated in sacrifices and that are, therefore, slain for nothing, and that has not been offered to the gods and Pitris with the aid of the ordinances. There is not the slightest doubt that a person by eating such meat goes to Hell. If one eats the meat that has been sanctified in consequence of its having been procured from animals dedicated in sacrifices and that have been slain for the purpose of feeding Brahmanas, one incurs a little fault. By behaving otherwise, one becomes stained with sin. That wretch among men who slays living creatures for the sake of those who would eat them, incurs great demerit. The eater's demerit is not so great. That wretch among men who, following the path of religious rites and sacrifices laid down in the Vedas, would kill a living creature from desire of eating its flesh, would certainly become a resident of hell. That man who having eaten flesh abstains from it afterwards, attains to great merit in consequence of such abstention from sin. He who arranges for obtaining flesh, he who approves of those arrangements, he who slays, he who buys or sells, he who cooks, and he who eats, are all regarded as eaters of flesh. I shall now cite another authority, depending upon that was declared by the ordainer himself, and established in the Vedas.