Kaṭha Upaniṣad 69

69

yasminn idaṃ vicikitsanti mṛtyo yat sāmparāye mahati brūhi nas tat /
yo 'yaṃ varo gūḍham anupraviṣṭo nānyaṃ tasmān naciketā vṛṇīte ///1,1.29 //

29. Oh Death, tell us that in which men have this doubt, and which is about the great hereafter; no other boon doth Nachiketas crave, than this which entered into the secret.