2.26
अथ चैनं नित्यजातं नित्यं वा मन्यसे मृतम् | तथापि त्वं महाबाहो नैनं शोचितुमर्हसि ||२६||
atha chainaṁ nitya-jātaṁ nityaṁ vā manyase mṛtam tathāpi tvaṁ mahā-bāho nainaṁ śhochitum arhasi
Translation
But if you think the soul is perpetually born and perpetually dies, still O mighty-armed Arjuna, you have no reason to lament.
Interpretation
Krishna offers a concession: even if you do not accept the soul's eternity (taking the materialist position that birth and death are real), there is still no reason to grieve — because death is inevitable and natural. Either way — whether the soul is eternal or whether birth and death are real — grief is irrational.