KAṬHA UPANISHAD · 1.1.14

प्र ते ब्रवीमि तदु मे निबोध
स्वर्ग्यमग्निं नचिकेतः प्रजानन् ।
अनन्तलोकाप्तिमथो प्रतिष्ठां
विद्धि त्वमेतं निहितं गुहायाम् ॥ १४॥

pra te bravīmi tadu me nibodha
svargyamagniṃ naciketaḥ prajānan ।
anantalokāptimatho pratiṣṭhāṃ
viddhi tvametaṃ nihitaṃ guhāyām ॥ 14॥

“Hearken to me and understand, O Nachiketas; I declare to thee that heavenly Flame, for I know it. Know this to be the possession of infinite existence and the foundation and the thing hidden in the secret cave of our being.”

Sri Aurobindo · CWSA 18, p. 104