Mahabharata Anushasna Parva Chapter 141:3

Mahabharata Anushasna Parva (Dana Dharma Parva) Chapter 141:3 Without doubt, the observance of fasts (i.e., subjugation of the senses) is always the duty of the Brahmana. When the Brahmana succeeds in properly observing all his duties, he attains to identity with Brahma.[] The proper observance of the duties of Brahmacharya, O goddess, are his ritual. The observance of vows and the investiture with the sacred thread are his other duties. It is by these that he becomes truly regenerate. He becomes a Brahmana for worshipping his preceptors and other seniors as also the deities. Verily, that religion which has for its soul the study of the Vedas is the source of all piety. Even that is the religion which those embodied creatures who are devoted to piety and duty should observe and practise." 'Uma said, "O holy one, my doubts have not been dispelled. It behoveth thee to explain in detail what the duties are of the four respective orders of men." 'Maheswara said, "Listening to the mysteries of religion and duty, observance of the vows indicated in the Vedas, attention to the sacred fire, and accomplishment of the business of the preceptor, leading a mendicant life, always bearing the sacred thread, constant recitation of the Vedas, and rigid observance of the duties of Brahmacharya, are the duties of the Brahmana. After the period of study is over, the Brahmana, receiving the command of his preceptor, should leave his preceptor's abode for returning to his father's house. Upon his return he should duly wed a wife that is fit for him. Another duty of the Brahmana consists in avoiding the food prepared by the Sudra. Walking along the path of righteousness, always observing fasts and the practices of Brahmacharya, are his other duties.[] The householder should keep up his domestic fire for daily worship. He should study the Vedas. He should pour libations in honour of the Pitris and the deities. He should keep his senses under proper control. He should eat what remains after serving gods and guests and all his dependants. He should be abstemious in food, truthful in speech, and pure both externally and internally. Attending to guests is another duty of the householder, as also the keeping up of the three sacrificial fires. The householder should also attend to the ordinary sacrifices that go by the name of Ishti and should also dedicate animals to the deities according to the ordinances. Indeed, the performance of sacrifices is his highest duty as also a complete abstention from injury to all creatures. Never to eat before serving the deities and guests and dependants is another duty of the householder. The food that remains after serving gods and guests and dependants is called Vighasa. The householder should eat Vighasa. Indeed, to eat after the members of one's family including servants and other dependants, is regarded as one of the special duties of the regenerate householder, who should be conversant with the Vedas. The conduct of husband and wife, in the case of householder, should be equal. He should every day make offerings of flowers and other articles unto those deities that preside over domesticity.