B.G 2.26
अथ चैनं नित्यजातं नित्यं वा मन्यसे मृतम्। तथापि त्वं महाबाहो नैनं शोचितुमर्हसि ॥२-२६॥
atha cainaṁ nityajātaṁ nityaṁ vā manyase mr̥tam। tathāpi tvaṁ mahābāho nainaṁ śocitumarhasi ॥2-26॥
O mighty armed, even if you regard the being as inevitably born, and inevitably dying, it is not right for you to grieve.
Gīta Bhāshya 2.26
Birth and death are inevitable and hence there is no need to lament.
Even though Jiva is everlasting, it still goes through the process of being born and dying in the form of uniting and separating from the body. Hence the "atha ca" verse.
Gīta Tātparya 2.26
The word 'nityam' in this verse means 'inevitable' based on context and dictionary.
Despite the explanations provided so far, you must still wait to get liberated. In the meantime, birth and death are both subject to the law and unavoidable. With this minimal knowledge, it is clear that grieving is not worth it.
'The word 'nitya'means that which is eternal. It also means that which cannot be avoided" - states "shabdanirnaya" dictionary.
The word 'nitya' should be interpreted as that which is inevitable. Because is the next verse "jātasya hi dhruvaḥ", a similar meaning is expressed using the word "dhruvaḥ".
