B.G 2.12

Never was there a time when I did not exist, nor you, nor these kings. Surely, nor will there be a time in the future when we all will cease to exist.

Gīta Bhāshya 2.12

Similar to God, the individual being is also eternal.

Why so (why should not one worry)? 'na-tvevaham' verse gives the answer. There is no need to prove the eternality of God (Ishwara). Taking Him as an example, the 'na-tve' verse explains: "The way I am famous in all the Vedas as eternal, similarly you, all the kings, are also eternal".

Gīta Tātparya 2.12

God has no destruction of the body or the self. The individual self is indestructible, but its body goes through destruction.

Indeed, it is due to attachment to relatives that you cease from your own duty, 'sva-dharma'. Is this because of fear of the physical body's destruction or the destruction of conscious-being? Since the body is inherently destructible, there is no reason to fear. Nor should there be fear of the destruction of conscious-being, due to its indestructibility. So much, there is no destruction of my supreme consciousness. Likewise, of yours and others.

"He is the eternal among the eternal, the conscious among the conscious-beings, the one who fulfils the desires of the many."

- stated thus in the Vedas.

"The cycle of birth and death, the union and separation from the body, is something that is sought for the liberation of ordinary beings, but it never applies to Lord Hari."

- stated thus in the Skanda Purana.

Even though Krishna is Lord, because of delusion, if someone doubts eternality in Him of both kinds, it is clarified by stating 'natvevaham' i.e., "never was there a time when I did not exist".

These doubts are not present in Arjuna. Even then, the Lord clarifies for the sake of benefiting the world. Even though this episode happened privately (only between Arjuna and Krishna), in the form of Vyasa, he published it to the world.