Bhagavad Gita 2.20
It was not born; it will never die, nor, once having been, can it cease to exist. Unborn, eternal, ever-enduring, yet most ancient, the spirit does not die when the body is dead.
न जायते म्रियते वा कदाचि
न्नायं भूत्वा भविता वा न भूयः।
अजो नित्यः शाश्वतोऽयं पुराणो
न हन्यते हन्यमाने शरीरे॥na jāyate mriyate vā kadāci
nnāyaṃ bhūtvā bhavitā vā na bhūyaḥ|
ajo nityaḥ śāśvato'yaṃ purāṇo
na hanyate hanyamāne śarīre||
English translation (above): Shri Purohit Swami (1935), public domain. Sanskrit text via github.com/gita/gita (Unlicense).