The impermanent has no reality; reality lies in the eternal. Those who have seen the boundary between these two have attained the end of all knowledge. 17 Realize that which pervades the universe and is indestructible; no power can affect this unchanging, imperishable reality. 18 The body is mortal, but that which dwells in the body is immortal and immeasurable. Therefore, Arjuna, fight in this battle.