Mahabharata 3.199.9

3.199.9

agnayo māṃsakāmāśca ityapi śrūyate śrutiḥ |
yajñeṣu paśavo brahmanvadhyante satataṃ dvijaiḥ |
saṃskṛtāḥ kila mantraiśca te'pi svargamavāpnuvan || 9 ||

And at sacrifices animals are invariably killed by regenerate Brahmanas, and these animals being purged of sin, by incantation of hymns, go to heaven. If, O Brahmana, the sacred fire had not been so fond of animal food in ancient times, it could never have become the food of any one. And in this matter of animal food, this rule has been laid down by Munis:--Whoever partakes of animal food after having first offered it duly and respectfully to the gods and the manes, is not polluted by the act. And such a man is not at all considered to have partaken of animal food, even, as a Brahmacharin having intercoursed with his wife during the menstrual period, is nevertheless considered to be a good Brahmana. After consideration of the propriety and impropriety of the matter, this rule has been laid down. King Saudasa, O Brahmana, when under a curse, often used to prey upon men; what is thy opinion of this matter? And, O good Brahmana, knowing this to be the consequence of my own actions, I obtain my livelihood from this profession. The forsaking of one's own occupation is considered, O Brahmana, to be a sin, and the act of sticking to one's own profession is without doubt a meritorious act. The Karma of a former existence never forsakes any creature. And in determining the various consequences of one's Karma, this rule was not lost sight of by the Creator.