Bhagavad Gita Chapter 2, Verse 20

न जायते म्रियते वा कदाचिन्नायं भूत्वा भविता वा न भूयः | अजो नित्यः शाश्वतोऽयं पुराणो न हन्यते हन्यमाने शरीरे ||

na jāyate mriyate vā kadācin nāyaṁ bhūtvā bhavitā vā na bhūyaḥ ajo nityaḥ śāśvato 'yaṁ purāṇo na hanyate hanyamāne śarīre

This is never born nor dies. Having come to be, it will never cease to be. Unborn, eternal, permanent, and primordial, it is not killed when the body is killed.

Arjuna fears killing his relatives, so Krishna reveals what death can't touch. Consciousness is 'aja' (unborn—it never came to be because it IS being), 'nitya' (eternal—outside time), 'śāśvata' (unchanging), and 'purāṇa' (primordial—foundational awareness). The radical claim: 'na hanyate hanyamāne śarīre'—consciousness isn't killed when the body is killed. What you fundamentally are doesn't participate in birth and death. Bodies come and go, but the awareness witnessing them remains untouched, like space is untouched by clouds passing through it.