Wisdom from the Bhagavad Gita 63

40. There is no entity on earth, or again in heaven among the Devas, that is devoid of these three Gunas, born of Prakriti. 

41. Of Brâhmanas and Kshatriyas and Vaishyas, as also of Sudras, O scorcher of foes, the duties are distributed according to the Gunas born of their own nature. 

42. The control of the mind and the senses, austerity, purity, forbearance, and also uprightness, knowledge, realization, belief in a hereafter—these are the duties of the Brâhmanas, born of their own nature. 

43. Prowess, boldness, fortitude, dexterity, and also not flying from battle, generosity, and sovereignty are the duties of the Kshatriyas, born of their own nature. 

44. Agriculture, cattle-rearing, and trade are the duties of the Vaishyas, born of their own nature; and action consisting of service is the duty of the Sudras, born of their own nature. 

45. Devoted each to his own duty, man attains the highest perfection. How engaged in his own duty, he attains perfection, that hear. 

46. From whom is the evolution of all beings, by whom all this is pervaded, worshipping Him with his own duty, a man attains perfection. 

47. Better is one's own Dharma, though imperfect, than the Dharma of another well-performed. He who does the duty ordained by his own nature incurs no evil. 

48. One should not relinquish, O son of Kunti, the duty to which one is born, though it is attended with evil; for, all undertakings are enveloped by evil, as fire by smoke. 

49. He whose intellect is unattached everywhere, who has subdued his heart, whose desires have fled, he attains by renunciation to the supreme perfection, consisting of freedom from action. 

—Bhagavad Gita, 18:40-49