2.21 Whosoever knows It to be indestructible, eternal, unborn and inexhaustible, how can that man slay, O Arjuna, or cause to be slain?

2.21 Veda etc. Whosoever, because of his realisation, under-stands this Self as 'This neither slays [any one]. nor is This slain [by any one] - how could there be any bondage for him ?

2.21. O son of Pritha, how can that man, who knows this embodied soul to be indestructible, eternal, unborn, and immutable, slay anyone or cause anyone to be slain? Commentary: The meaning is—"Vedāvināśinam... ghātayati hanti kam"—One who truly realizes that this embodied soul is never destroyed, never undergoes any change, is never born, and never suffers any kind of diminution—how can such a person slay anyone or cause anyone to be slain? That is to say, such a person cannot have any inclination to kill others or cause others to be killed. He can neither become the doer of any action nor the instigator of any action. Here, by describing the embodied soul as indestructible, eternal, unborn, and immutable, the Lord has negated all six modifications (vikāras) within it. For instance, by calling it "indestructible," the modification in the form of death is negated; by "eternal," the modification of changing states and growth is negated; by "unborn," the modification of birth and the state of existence that follows birth is negated; and by "immutable," the modification of decay is negated. In the embodied soul, not the slightest modification occurs due to any action. If the Lord's intention in the phrases "na hanyate hanyamāne śarīre" (It is not slain when the body is slain) and "kaṁ ghātayati hanti kam" (slay anyone or cause anyone to be slain) was merely to negate the soul's becoming an agent or an object of action, then why speak here of killing and being killed instead of doing and not doing? The answer is that, since the context is that of war, it is essential to state here that the embodied soul does not become the killer in battle, because there is no agency in it. When the embodied soul cannot become the killer, i.e., the agent, then how can it become the one slain, i.e., the object of the action? The purport is that this embodied soul is neither the agent nor the object of any action. Therefore, one should not grieve over killing and being killed; rather, one should perform the duty that has come to hand in accordance with the injunctions of the scriptures. Connection: In the preceding verses, the immutability of the soul has been described. In the following verse, the same is described by way of an illustration.