Verse 2.20

न जायते म्रियते वा कदाचि न्नायं भूत्वा भविता वा न भूयः। अजो नित्यः शाश्वतोऽयं पुराणो न हन्यते हन्यमाने शरीरे।।2.20।।

na jāyate mriyate vā kadāchin nāyaṁ bhūtvā bhavitā vā na bhūyaḥ ajo nityaḥ śhāśhvato ’yaṁ purāṇo na hanyate hanyamāne śharīre

Meaning

It's not born, doesn't ever die. It's always been, always will be. It's unborn, eternal, unchanging, ancient AF. Killing the body doesn't kill it.

Commentary

Yo, this Self, Atman, is totally immune to all that six-stage drama of life—birth, existence, growth, change, decline, death. It's unbreakable, un-dimminishable, doesn't grow or shrink, it's always the same. Birth and death? That's only for the physical body, fam. The immortal, all-pervading Self is untouched by that.