Wisdom from the Bhagavad Gita 4

19. He who takes the Self to be the slayer, he who takes It to be the slain, neither of these knows. It does not slay, nor is It slain. 

20. This is never born, nor does It die. It is not that not having been It again comes into being. Or according to another view: It is not that having been It again ceases to be. This is unborn, eternal, changeless, ever-Itself. It is not killed when the body is killed. 

21. He that knows This to be indestructible, changeless, without birth, and immutable, how is he, O son of Prithâ, to slay or cause another to slay? 

22. Even as a man casts off worn-out clothes, and puts on others which are new, so the embodied casts off worn-out bodies, and enters into others which are new. 

23. This Self, weapons cut not; This, fire burns not; This, water wets not; and This, wind dries not. 

24. This Self cannot be cut, nor burnt, nor wetted, nor dried. Changeless, all-pervading, unmoving, immovable, the Self is eternal. 

25. This Self is said to be unmanifested, unthinkable, and unchangeable. Therefore, knowing This to be such, you ought not to mourn. 

26. But if you should take This to have constant birth and death, even in that case, O mighty-armed, you ought not to mourn for This. 

27. Of that which is born, death is certain, of that which is dead, birth is certain. Over the unavoidable, therefore, you ought not to grieve. 

28. All beings are unmanifested in their beginning, O Bhârata, manifested in their middle state and unmanifested again in their end. What is there then to grieve about?

—Bhagavad Gita, 2:19-28