Chāndogya Upaniṣad 5.18.1

5.18.1

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 \\518.1\

1. Then he said to them: ‘Verily, indeed, you here eat food, knowing this Universal Ātman (Soul) as if something separate. He, however, who reverences this Universal Ātman (Soul) that is of the measure of the span —thus, [yet] is to be measured by thinking of oneself —he eats food in all worlds, in all beings, in all selves.