Srimad Bhagvata Mahapurana: Book 7: Chapter 11: Verses 18-35
An inquiry into right conduct
One may live by (what are known as) Rta and Amrta or (even) by Mrta and Pramrta. One may (also) live by Satyanrta, but under no circumstance by Swavrtti (a dog's (living). Gathering ears of corn left by the owner while reaping a harvest or gleaning foodgrains lying scattered in a grain-market after the heaps have been sold off or removed is called Rta (lit., right or true); that which is got unasked is called Amrta (nectar). Daily begging (of foodgrains) is Mrota (death); white agriculture is called Pramrta (lit., greater death, so-called because it involves the destruction of many living beings). Trade is (what goes by the name of) Satyanrta (a mixture of truth and falsehood); while service rendered to those belonging to a lower grade is (what is meant by) a dog's living. A Brahmana as well as a Ksatriya should always shun this detested calling. (For) a Brahmana is an embodiment of all the (four) Vedas, while a Ksatriya (lit., a ruler of men) is the personification of all the gods. Control of mind and the senses, austerity (fasting etc.), purity (of body), contentment, forgiveness, straightforwardness, wisdom (discrimination), compassion, devotion to the immortal Lord (Visnu) and veracity are the characteristics of a Brahmana. A martial spirit, valour, fortitude, audacity, liberality, self-control, forgiveness, devotion to the Brahmana race, benignity and protection (of the weak) constitute the characteristics of a Ksatriya. Devotion to the gods, to one's preceptor and to the immortal Lord (Visnu); promotion of the three objects of human pursuit (viz., religious merit, worldly riches and sensual enjoyment); belief in the existence of God, in life after death, and so on; constant exertion (for the acquisition of wealth) and dexterity (in acquiring it) are the characteristics of a Vaisya. (And) submissiveness, purity, guilelessly ministering to one's master, performance of (the five daily) sacrifices unaccompanied by (the recitation of) Mantras (sacred texts), non-thieving, truthfulness and protection of cows and the Brahmanas are indeed the characteristics of a Sudra. And the duty of women devoted to their husband (lit., looking upon their husband as a deity) is to serve him, to do good offices to him, to humour his relations and constantly to observe his sacred vows. Herself remaining adorned and keeping her utensils etc., well-scoured at all times, a virtuous wife should serve her husband by thoroughly sweeping her house and plastering it (with cow-dung etc.), by drawing auspicious diagrams and spherical designs (on the floor with colours), through sense-objects-great and small-desired by him, through modesty and control of the senses, through truthful and agreeable words and (above all) through love at opportune moments.
Contented (with her resources) and not coveting even that which is available (to her), diligent, conversant with Dharma (what is right), agreeable and truthful of speech (not only to her husband but to all), vigilant, pure (of body) and full of affection, she should gratify her husband unless he is fallen (guilty of any of the five major sins). A wife who serves her husband, regarding him as an image of Sri Hari (Lord Visnu) and devoted to him as Goddess Laksmi is to Her Consort, rejoices in Vaikuntha (the realm of Sri Hari) like Sri (Laksmi) in the company of her husband, who (by virtue of her devotion) is sure to attain a form similar to that of Sri Hari (Himself).
The calling of mixed races such as the Antyajas  (those belonging to the lowest grade in society) and Antevasayis . (lit., those living at the end of a town or village ), other than those who are thieves and given to (other) sinful pursuits, should be the same as has been (hereditarily) followed in their respective families. (30) Generally the course of conduct determined by the innate disposition (according as it is Sattvika, Rajasiks or Tamasika) of men (belonging to the various grades of society and stages in life) in all ages has been declared by men whose eye is the Veda as conducive to happiness both here and hereafter, O Yudhisthira ! A man following a vocation determined by his natural disposition (as revealed by his birth) and (scrupulously) discharging his duties bids fair to attain by degrees the state of a Gunatita (one who has transcended the three Gunas or modes of Prakrti), relinquishing (later on) his natural pursuits (as well). Being repeatedly sown (with seeds), a field will automatically become sterile (one day). It will no more be capable of yielding any crops; may, (even) the seed sown (in it) will perish. (Even) so by over-indulgence in the objects of senses the mind, the seat of desires (in their latent form) is sure to get fully disgusted (with them), 0 king, but not so by driblets of enjoyment, like fire (that is extinguished by pouring large quantities of ghee but not so by drops of it). If what has been declared to be a characteristic of the grade in society of a (particular) man is perceived even in another (a man belonging to a different class), the latter should be distinctively called by that very denomination (caste).
Thus ends the eleventh discourse entitled "An inquiry into right conduct," forming
part of the dialogue between Emperor Yudhisthira and the sage Narada,
in Book Seven of the great and glorious Bhagavata-Purana, otherwise known as the Paramahamsa-Samhita..