Did Krishna command Arjuna to fight and kill without compunction?
We must understand here the historical context of this command, namely the events of the Maha-bharata. Prefatorily, the ancient Greek ambassador to India, Megasthenes, in his famous book on India, insists that Indians excel other nations in their lofty battlefield ethics. Non-combatants are never in danger, a far cry from the gruesome battlefield descriptions of ancient Greco-Roman historians, not to speak of Attila.
In effect, Arjuna was fighting for constitutional monarchy against professional warriors who sought to usurp the throne and thus destroy the rule of law. All the enemy combatants stood on the battlefield against the advice and pleas of Krishna and many other wise persons. One may even say that Krishna’s advice to Arjuna is quite similar to the teachings of any prestigious military academy of our time: one must fight courageously for justice, without fear or sentimentality, emotions that would jeopardize freedom and justice.
The Gita makes clear that non-warriors who do not fight on behalf of a legitimate government, may not commit violence against anyone. Krishna makes this clear in the Gita with the use of the word ‘ahimsa’, non-violence, and with his emphatic stricture that one may not perform the duties of another varna/caste. Warrior-dharma is tightly circumscribed in the Maha-bharata: only tose of the warrior class may use violence, and only against enemy combatants, in the service of a legitimate government, and then only for the cause of justice. Again, this principle is not much different than the standards of modern constitutional states.