|| 2.26 ||

अथ चैनं नित्यजातं नित्यं वा मन्यसे मृतम्। तथापि त्वं महाबाहो नैवं शोचितुमर्हसि।।

atha cainaṁ nitya-jātaṁ nityaṁ vā manyase mṛtam tathāpi tvaṁ mahā-bāho naivaṁ śocitum arhasi

atha (if) ca (and) enam (this soul) nitya-jātam (always born) nityam (always) vā (or) manyase (you think) mṛtam (dead) tathā api (still) tvam (you) mahā-bāho (O mighty-armed) na (not) evam (like this) śocitum (to grieve) arhasi (deserve)

If, however, you think that the soul [or the symptoms of life] is always born and dies forever, you still have no reason to lament, O mighty-armed Arjuna.

Kṛṣṇa uses a ‘worst-case scenario’ logic. Even if one does not believe in the eternal soul and thinks life is just a temporary chemical process that is born and dies, there is still no logical reason for extreme lamentation. Change is the fundamental law of the physical world. By addressing Arjuna as ‘Mahā-bāho’, He reminds him of his strength as a warrior which should not be weakened by philosophical doubts.