I acknowledge this graphic from the Net.
He who is eternal, indestructible, uncreated, and limitless
Who does he cause to kill
Who can he kill?
In the commentary I have of Shankara on Gita, translated by Alladi Mahadeva Sastri first in 1897, over 6 pages are devoted to explanation of this seemingly simple verse.
Shankara in his comment on the previous verse refers to the Self as devoid any transformation, as one that stays as is, with no creation or destruction or growth or any modification. Self is the state of being. This means it is devoid of action.
In a sense, in my own interpretation, this is the concept of the inactive, potential energy filled Purusha in Sankhya Yoga theory. In my mind’s eye, this is how I view Shiva, the silent and potent energy. Purusha has the active principle of Prakriti inbuilt in it, and in Shiva the active half is of Shakti, as the duality. However, in Krishna’s singularity concept of Self as the ultimate Brahman, that duality becomes the singular inactive and yet all powerful That, one that is eternal and uncreated, and still That which creates and what eventually dies as well.
In the absence of any action how can that entity kill or cause to kill?
I can understand the statement that it cannot kill as it is inactive. However, if that entity causes other creations, which in turn die, why cannot they cause others to die?
This then raises the question of what death is.
Is death an end or is it a beginning? If as if our scriptures say existence is a continuum, which Krishna elaborates on later, death is not an end. It may not be a beginning, yet a gateway to another existence. What then would killing achieve?
Does destroying the mind body, which in any case will destruct on its own at some point, equal killing? Shankara says it is about the mental makeup, the intent. If that killing is with the understanding of the continuance of the energy despite the destruction of the mind body, there is no intent to destroy, therefore no intent to kill.
You may ask if this is specious logic. I don’t know. It is the response of the doer. If the doer has renounced all intent to destroy and yet carries out the act of destruction as a process, would it be different?
Look at nature. Thousands are killed in earthquakes, volcanic eruptions and tsunamis. Would there be a point to be proved in labelling nature as a murderer? If you drive over an anthill and kill a few thousand ants, would you be a murderer in the ant world? When countries battle and millions are killed, why is called war and not murder?
If individuals are killed, it is murder, punishable. If millions are killed it is war, and heroes are rewarded. Is that logic any better? Societal rules are formed looking at death as an end, something that can be prevented. Krishna advises us to look at it differently.
What kind of society will we become if we did? Would we become saints or monsters?
Later verses clarify this point.