The Great Epic of the Bhārata dynasty 6.24.49

6.24.49

dūreṇa hyavaraṃ karma buddhiyogāddhanaṃjaya |
buddhau śaraṇamanviccha kṛpaṇāḥ phalahetavaḥ || 49 ||

Be thou, O Arjuna, free from them, unaffected by pairs of contraries (such as pleasure and pain, heat and cold, etc.), ever adhering to patience without anxiety for new acquisitions or protection of those already acquired, and self-possessed, whatever objects are served by a tank or well, may all be served by a vast sheet of water extending all around; so whatever objects may be served by all the Vedas, may all be had by a Brahmana having knowledge (of self or Brahma). Thy concern is with work only, but not with the fruit (of work). Let not the fruit be thy motive for work; nor let thy inclination be for inaction. Staying in devotion, apply thyself to work, casting off attachment (to it), O Dhananjaya, and being the same in success or unsuccess. This equanimity is called Yoga (devotion). Work (with desire of fruit) is far inferior to devotion, O Dhananjaya. Seek thou the protection of devotion. They that work for the sake of fruit are miserable. He also that hath devotion throws off, even in this world, both good actions and bad actions. Therefore, apply thyself to devotion. Devotion is only cleverness in action. The wise, possessed of devotion, cast off the fruit born of action, and freed from the obligation of (repeated) birth, attain to that region where there is no unhappiness. When thy mind shall have crossed the maze of delusion, then shalt thou attain to an indifference as regards the hearable and the heard.