Mbh 12.295.1a

"'"Parasara said, 'In the Brahmana, wealth acquired by acceptance of gifts, in the Kshatriya that won by victory in battle, in the Vaisya that obtained by following the duties laid down for his order, and in the Sudra that earned by serving the three other orders, however small its measure, is worthy of praise, and spent for the acquisition of virtue is productive of great benefits. The Sudra is said to be the constant servitor of the three other classes. If the Brahmana, pressed for a living, betakes himself to the duties of either the Kshatriya or the Vaisya, he does not fall off from righteousness. When, however, the Brahmana betakes himself to the duties of the lowest order, then does he certainly fall off. When the Sudra is unable to obtain his living by service of the three other orders, then trade, rearing of cattle, and the practice of the mechanical arts are lawful for him to follow. Appearance on the boards of a theatre and disguising oneself in various forms, exhibition of puppets, the sale of spirits and meat, and trading in iron and leather, should never be taken up for purposes of a living by one who had never before been engaged in those professions every one of which is regarded as censurable in the world. It hath been heard by us that if one engaged in them can abandon them, one then acquires great merit. When one that has become successful in life behaves sinfully in consequence of one's mind being filled with arrogance, one's acts under such circumstances can never pass for authority. It is heard in the Puranas that formerly mankind were self-restrained; that they held righteousness in great esteem; that the practices they followed for livelihood were all consistent with propriety and the injunctions laid down in the scriptures, and that the only punishment that was required for chastising them when they went wrong was the crying of fie on them.