A boy sent to Yama, the lord of death, refuses wealth and long life and asks instead: what happens after we die?
Young Nachiketa was sent by his father, in anger, to the house of Death. Yama, impressed by the boy's courage, offered him three boons. Nachiketa's third request was the deepest: teach me the truth of what survives the body. Yama first tried to distract him with kingdoms and pleasures, but the boy refused them all. And so Yama taught him: the atman — the Self — is not born and does not die; it is smaller than the smallest, greater than the greatest, and it is the same in every being.
The lesson
The soul is neither born nor does it die. What passes through lifetimes is not the body, but the witness within.