Synonyms:

dehi–the owner of the material body; nityam–eternally; avadhyah–cannot be killed; ayam–this soul; dehe–in the body; sarvasya–of everyone; bharata–O descendant of Bharata; tasmat–therefore; sarvani–all; bhutani–living entities (that are born); na–never; tvam–yourself; socitum–to lament; arhasi–deserve.

Translation:

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.