Kaṭhopaniṣad 1.19-20—The Third Boon

Death: “O Naciketā, this is for you the boon about the Fire that leads to heaven, for which you prayed through the second boon. People will speak of this Fire as yours indeed. O Naciketā, ask for the third boon." Naciketā: “This doubt that arises, consequent on the death of a man—some saying, ‘It exists,’ and others saying, ‘It does not exist.’ I would know this, under your instruction. This is the third of all the boons.”