Bhagavad Gita 2.30
देही नित्यमवध्योऽयं देहे सर्वस्य भारत । तस्मात्सर्वाणि भूतानि न त्वं शोचितुमर्हसि ॥
dehī nityam avadhyo 'yaṃ dehe sarvasya bhārata | tasmāt sarvāṇi bhūtāni na tvaṃ śocitum arhasi ||
Translation
The embodied one in the body of all beings is ever indestructible, O descendant of Bharata. Therefore you should not grieve over any being.
Reflection
Which person did you stop treating as deathless when you started treating them as lost?
Read this verse in its chapter: Chapter Two
The summary line of the section on the deathless self. Avadhyaḥ. Not killable. Sarvasya, of every being. The teaching is not about Arjuna's family alone. The same self that cannot be reached by a weapon in his uncles is the same self in everyone he is grieving for and everyone he is not. Sarvāṇi bhūtāni, all beings: the scope of the consolation widens. Krishna will turn now from the question of the self to the question of action; he closes the metaphysical section here so the next section can rest on it.