Member-only story
न त्वेवाहं जातु नासं न त्वं नेमे जनाधिपा |
न चैव न भविष्याम: सर्वे वयमत: परम् || 12||
Certainly, there was never a time when I did not exist, nor did you, nor did these kings; nor shall we cease to exist in the future.
The double negative indicates that Bhagwan Shri Krishna is eternal because never was there a time when he was not.
Another eternal entity as highlighted by Bhagwan Shri Krishna is the ‘Soul’ and that is the reason that wise never laments the birth and death of the physical body because the soul that resides within the body is eternal.
By pointing this out, Bhagwan Shri Krishna highlights the fact that the Kings that Arjuna is going to fight existed before this time, and by slaying them he cannot destroy their souls as their souls like the rest of them are eternal. Thus there is no point in lamenting the loss of his friends and family that will result from the war that Arjuna was hesitating to fight.