CHĀNDOGYA UPANISHAD · 6.15.1

पुरुषं सोम्योतोपतापिनं ज्ञातयः पर्युपासते जानासि मां जानासि माम् इति ।
तस्य यावन् न वाङ् मनसि संपद्यते मनः प्राणे प्राणस् तेजसि तेजः परस्यां देवतायां तावज् जानाति ॥

puruṣaṃ somyotopatāpinaṃ jñātayaḥ paryupāsate jānāsi māṃ jānāsi mām iti ।
tasya yāvan na vāṅ manasi saṃpadyate manaḥ prāṇe prāṇas tejasi tejaḥ parasyāṃ devatāyāṃ tāvaj jānāti ॥

'If a man is ill, his relatives assemble round him and ask: "Dost thou know me? Dost thou know me?" Now as long as his speech is not merged in his mind, his mind in breath, breath in heat (fire), heat in the Highest Being (devatâ), he knows them.

F. Max Müller · The Upanishads, Sacred Books of the East 1 (1879)