Chāndogya Upaniṣad 5.17.2

5.17.2

atsy annaṃ paśyasi priyam \
atty annaṃ paśyati priyaṃ bhavaty asya brahmavarcasaṃ kule ya etam evam ātmānaṃ vaiśvānaram upāste \
pādau tv etāv ātmana iti hovāca \
pādau te vyamlāsyetāṃ yan māṃ nāgamiṣya iti \\517.2\

2. You eat food; you see what is pleasing. He eats food; he sees what is pleasing. There is eminence in sacred knowledge in the family of him who reverences that Universal Ātman (Soul) thus.

That, however, is only the feet of the Ātman (Soul),’ said he. ‘Your feet would have withered away, if you had not come unto me.’