Chandogya Upanishad 5.18

tān hovāca ete vai khalu yūyaṃ pṛthag ivemam ātmānaṃ vaiśvānaraṃ vidvāṃso 'nnam attha yas tv etam evaṃ prādeśamātram abhivimānam ātmānaṃ vaiśvānaram upāste sa sarveṣu lokeṣu sarveṣu bhūteṣu sarveṣv ātmasv annam atti

Then he said to them all: 'You eat your food, knowing that Vaisvânara Self as if it were many. But he who worships the Vaisvânara Self as a span long, and as identical with himself, he eats food in all worlds, in all beings, in all Selfs.

tasya ha vā etasyātmano vaiśvānarasya mūrdhaiva sutejāś cakṣur viśvarūpaḥ prāṇaḥ pṛthagvartmātmā saṃdeho bahulo bastir eva rayiḥ pṛthivy eva pādāv ura eva vedir lomāṇi barhir hṛdayaṃ gārhapatyo mano 'nvāhāryapacana āsyam āhavanīyaḥ

'Of that Vaisvânara Self the head is Sutegas (having good light), the eye Visvarûpa (multiform), the breath Prithagvartman (having various courses), the trunk Bahula (full), the bladder Rayi (wealth), the feet the earth, the chest the altar, the hairs the grass on the altar, the heart the Gârhapatya fire, the mind the Anvâhârya fire, the mouth the Âhavanîya fire.