2-20

न जायते म्रियते वा कदाचित् 
नायम् भूत्वा भविता वा न भूयः ।
अजो नित्यः शाश्वतोऽयम् पुराणो
न हन्यते हन्यमाने शरीरे ॥ २० ॥

na jAyate mriyate vA kadAcit 
nAyam bhUtvA bhavitA vA na bhUyaH |
ajo nityaH zAzvato'yam purANo
na hanyate hanyamAne zarIre || 20 ||

अयम् [ayam] The Self कदाचित् न जायते म्रियते वा [kadAcit na jAyate mriyate vA] is not born and never dies. अयम् [ayam] It न [na] has not भूत्वा [bhUtvA] come into being, भूयः न भविता वा [bhUyaH na bhavitA vA] neither will it ever cease to be. अयम् [ayam] It is अजः [ajaH] without birth, नित्यः [nityaH] ever-existing, शाश्वतः [zAzvataH] everlasting in a single form, पुराणः [purANaH] existing fresh from the beginning-less past. न हन्यते [na hanyate] The Self is not killed शरीरे हन्यमाने [zarIre hanyamAne] in a body that inevitably gets dead.

Due to the reasons mentioned above, the Self is indestructible. It isn’t subjected to the effects of nature and is not subject to birth and death. Birth and death are natural to inanimate objects- that’s the message conveyed in the Shloka.

‘It is born, it will die’: While birth and death are experienced all the time in bodies belonging to each one of us, they do not touch the Self at any time. The concepts of coming into being and ceasing to exist do not apply to the Self.

It means the Self has not come into being at the time of creation (at the beginning of the kalpa ), nor will it cease to exist at the time of destruction. Brahma, the principal engineer of the universe, is born and will eventually die. So do all the other great powers. Even in them, birth and death do not affect the Self.

In this way, the Self in each body is without birth. It is everlasting, doesn’t get destroyed and isn’t related to the unending series of cause-effect changes in the environment. Though ancient, the Self still seems to be new. It’s as though it had no past - this is the meaning expressed here. Thus, the Self is not killed inside the body that perishes.