Katha Upanishad Verse 1.1.29
Despite Yama’s attempts to lure him with worldly pleasures and celestial delights, Nachiketas remains steadfast. He insists on his third boon, demanding to know the secret of the “great hereafter,” for no other knowledge is as valuable to him.
Sanskrit Verse
यस्मिन्निदं विचिकित्सन्ति मृत्यो यत्साम्पराये महति ब्रूहि नस्तत् । योऽयं वरो गूढमनुप्रविष्टो नान्यं तस्मान्नचिकेता वृणीते ॥ २९ ॥
Transliteration
yasminnidaṃ vicikitsanti mṛtyo yatsāmparāye mahati brūhi nastat | yo’yaṃ varo gūḍhamanupraviṣṭo nānyaṃ tasmānnaciketā vṛṇīte || 29 ||
Translation
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.

Muni's Play