Bhagavad Gita Chapter 2.30
dehī nityam avadhyo ‘yaḿ
dehe sarvasya bhārata
tasmāt sarvāṇi bhūtāni
na tvaḿ śocitum arhasi
Translation
O descendant of Bharata, he who dwells in the body can never be slain. Therefore you need not grieve for any living being.