Know that this is what is called yoga: a release from contact with suffering. This yoga should be practiced with firm resolve and with a mind that does not lose heart.
Explanation
Krishna is instructing Arjuna on meditation, and here he sums up the state just described, a steady joy that no great sorrow can shake. He defines yoga (discipline, union) as dissociation (viyoga) from the bond with suffering (duḥkha-saṃyoga), and urges practice with firm resolve (niścaya) and an undepressed, undiscouraged mind (anirviṇṇa-cetas). Commentators differ on the last phrase, some reading it as persevering without despair, others as practicing without being weary of the effort or of the world.