The works of Ādi Śaṅkarācārya

Chāndogyopaniṣadbhāṣyam

Verse 69

दुग्धेऽस्मै वाग्दोहं यो वाचो दोहो-ऽन्नवानन्नादो भवति य एतामेव५ साम्ना-मुपनिषदं वेदोपनिषदं वेदेति ॥ ४ ॥

In plain words

Speech yields its milk for him. Whoever knows this secret doctrine of the Samans as the milking of speech becomes rich in food and an enjoyer of food—yes, whoever knows this secret doctrine.

Close to the Sanskrit

Speech milks the milking for him; who is the milking of speech, becomes possessor of food and eater of food, who knows thus this very upanishad of the samans, knows the upanishad.