Chandogya Upanishad 6.9

yathā somya madhu madhukṛto nistiṣṭhanti nānātyayānāṃ vṛkṣāṇāṃ rasān samavahāram ekatāṃ rasaṃ gamayanti

'As the bees, my son, make honey by collecting the juices of distant trees, and reduce the juice into one form,

te yathā tatra na vivekaṃ labhante 'muṣyāhaṃ vṛkṣasya raso 'smy amuṣyāhaṃ vṛkṣasya raso 'smīti evam eva khalu somyemāḥ sarvāḥ prajāḥ sati sampadya na viduḥ sati sampadyāmaha iti

'And as these juices have no discrimination, so that they might say, I am the juice of this tree or that, in the same manner, my son, all these creatures, when they have become merged in the True (either in deep sleep or in death), know not that they are merged in the True.

ta iha vyāghro vā siṃho vā vṛko vā varāho vā kīṭo vā pataṅgo vā daṃśo vā maśako vā yad yad bhavanti tad ābhavanti

'Whatever these creatures are here, whether a lion, or a wolf, or a boar, or a worm, or a midge, or a gnat, or a musquito, that they become again and again.

sa ya eṣo 'ṇimaitad ātmyam idaṃ sarvam tat satyam sa ātmā tat tvam asi śvetaketo iti bhūya eva mā bhagavān vijñāpayatv iti tathā somyeti hovāca

'Now that which is that subtile essence, in it all that exists has its self. It is the True. It is the Self, and thou, O Svetaketu, art it.' 'Please, Sir, inform me still more,' said the son. 'Be it so, my child,' the father replied.