Chandogya Upanishad 7.24

yatra nānyat paśyati nānyacchṛṇoti nānyad vijānāti sa bhūmā atha yatrānyat paśyaty anyacchṛṇoty anyad vijānāti tad alpam yo vai bhūmā tad amṛtam atha yad alpaṃ tan martyam sa bhagavaḥ kasmin pratiṣṭhita iti sve mahimni yadi vā na mahimnīti

'Where one sees nothing else, hears nothing else, understands nothing else, that is the Infinite. Where one sees something else, hears something else, understands something else, that is the finite. The Infinite is immortal, the finite is mortal.' 'Sir, in what does the Infinite rest?' 'In its own greatness—or not even in greatness.'

go'śvam iha mahimety ācakṣate hastihiraṇyaṃ dāsabhāryaṃ kṣetrāṇy āyatanānīti nāham evaṃ bravīmi bravīmīti hovāca anyo hy anyasmin pratiṣṭhita iti

'In the world they call cows and horses, elephants and gold, slaves, wives, fields and houses greatness. I do not mean this,' thus he spoke; 'for in that case one being (the possessor) rests in something else, (but the Infinite cannot rest in something different from itself.)