Wisdom from the Bhagavad Gita 15

21. Without hope, the body and mind controlled and all possessions relinquished, he does not suffer any evil consequences, by doing mere bodily action. 

22. Content with what comes to him without effort, unaffected by the pairs of opposites, free from envy, even-minded in success and failure, though acting, he is not bound.

23. Devoid of attachment, liberated, with mind centered in knowledge, performing work for Yajna alone, his whole Karma dissolves away.

24. The process is Brahman, the clarified butter is Brahman, offered by Brahman in the fire of Brahman; by seeing Brahman in action, he reaches Brahman alone. 

25. Some Yogis perform sacrifices to Devas alone, while others offer the self as sacrifice by the self in the fire of Brahman alone.

26. Some again offer hearing and other senses as sacrifice in the fire of control, while others offer sound and other sense-objects as sacrifice in the fire of the senses.

 27. Some again offer all the actions of the senses and the functions of the vital energy, as sacrifice in the fire of control in self, kindled by knowledge.
  
28. Others again offer wealth, austerity, and Yoga, as sacrifice, while still others, of self-restraint and rigid vows, offer study of the scriptures and knowledge, as sacrifice.

 29. Yet some offer as sacrifice, the outgoing into the in-coming breath, and the in-coming into the out-going, stopping the courses of the in-coming and out-going breaths, constantly practicing the regulation of the vital energy; while others yet of regulated food, offer in the Prânas the functions thereof. 

—Bhagavad Gita, 4:21-29