They are both ignorant, he who knows the soul to be capable of killing and he who takes it as killed; for verily the soul neither kills nor is killed.(B.G. 2:19) Gita Press Gorakphur trans.
Krishna is addressing Arjuna who is in a bind, double or treble even. To kill his relatives is a great sin even if they are transgressors yet his duty is to uphold dharma. Like Jules in Pulp Fiction he is not sure if he is the evil man or the shepherd:
Jules: There's a passage I got memorized. Ezekiel 25:17. "The path of the righteous man is beset on all sides by the inequities of the selfish and the tyranny of evil men. Blessed is he who, in the name of charity and good will, shepherds the weak through the valley of the darkness, for he is truly his brother's keeper and the finder of lost children. And I will strike down upon thee with great vengeance and furious anger those who attempt to poison and destroy My brothers. And you will know I am the Lord when I lay My vengeance upon you." Now... I been sayin' that shit for years. And if you ever heard it, that meant your ass. You'd be dead right now. I never gave much thought to what it meant. I just thought it was a cold-blooded thing to say to a motherfucker before I popped a cap in his ass. But I saw some shit this mornin' made me think twice. See, now I'm thinking: maybe it means you're the evil man. And I'm the righteous man. And Mr. 9mm here... he's the shepherd protecting my righteous ass in the valley of darkness. Or it could mean you're the righteous man and I'm the shepherd and it's the world that's evil and selfish. And I'd like that. But that shit ain't the truth. The truth is you're the weak. And I'm the tyranny of evil men. But I'm tryin', Ringo. I'm tryin' real hard to be the shepherd.
Krishna could be construed as offering Arjuna an antinomian gnostic way to cut the knot of the double bind. Nothing personal as Charlie Partana said in Prizzi’s Honor Or on the other hand it could be like what Bob Hope said when caught in flagrante “It’s not me”.
These are possible interpretations. My own view is that Krishna is like Winco (Wing Commander) in a British War Movie putting his men in the picture pointing at a map of the Ruhr Valley. The big picture is an impersonal one. However taking 2:19 on its own is as much a motive for inaction as action because Arjuna has not realised the non-dual truth and cannot use it as a motive. It is a blank picture for him that shimmers like a mirage of shraddha (faith). The personal dharma of the warrior caste draws its strength from the impersonal reality. In later chapters Krishna fills out the concept of personal duty and practice yet I believe that the knowledge of the impersonal is not a cold-blooded thing, the Julsian thang. You ought to suffer. Renunciation is a warrant of sincerity therefore just prior to his speech Jules says:
Jules: I want you to go in that bag, and find my wallet.
Pumpkin: Which one is it?
Jules: It's the one that says Bad Motherfucker. .........
Jules: I'm not giving you that money. I'm buying something from you. Wanna know what I'm buyin' Ringo?
Jules: Your life. I'm givin' you that money so I don't have to kill your ass. You read the Bible?
Pumpkin: Not regularly.
Then you can walk the land.