Chapter 2: Sloka 30

2.30

dehī nityam avadhyo ’yaṁ
dehe sarvasya bhārata
tasmāt sarvāṇi bhūtāni
na tvaṁ śocitum arhasi

dehī—the owner of the material body; nityam—eternally; avadhyaḥ—cannot be killed; ayam—this soul; dehe—in the body; sarvasya—of everyone; bhārata—O descendant of Bharata; tasmāt—therefore; sarvāṇi—all; bhūtāni—living entities (that are born); na—never; tvam—yourself; śocitum —to lament; arhasi— deserve.

O descendant of Bharata, he who dwells in the body is eternal and can never be slain. Therefore you need not grieve for any creature.