Kaṭha Upaniṣad 1.13

1.13

sa tvam agniṃ svargyam adhyeṣi mṛtyo prabrūhi taṃ śraddadhānāya mahyam /
svargalokā amṛtatvaṃ bhajanta etad dvitīyena vṛṇe vareṇa //

[Naciketas :] 12. In the heavenly world is no fear whatsoever. Not there art thou. Not from old age does one fear. Over both having crossed—hunger, and thirst too— Gone beyond sorrow, one rejoices in the heaven-world. 13. Thyself, O Death, understandest the heavenly fire. Declare it to me who have faith (śraddadhāna). Heaven-world people partake of immortality. This I choose with boon the second.