न जायते म्रियते वा कदाचिन्नायं भूत्वा भविता वा न भूयः ।अजो नित्यः शाश्वतोऽयं पुराणोन हन्यते हन्यमाने शरीरे ॥
na jāyate mriyate vā kadācinnāyaṃ bhūtvā bhavitā vā na bhūyaḥ |ajo nityaḥ śāśvato'yaṃ purāṇona hanyate hanyamāne śarīre ||
This self is never born and never dies; having come to be, it will never cease to be. Unborn, constant, eternal and ancient, it is not killed when the body is killed.
Explanation
Krishna continues teaching the grieving Arjuna about the self (ātman), the conscious being within, which he describes as without birth or death and ancient. Only the body is struck down in battle; the self is not touched. Commentators read the second line in two ways: either the self never came into being and never will, or, having always existed, it will never cease; both agree that it is deathless.