The works of Ādi Śaṅkarācārya

Chāndogyopaniṣadbhāṣyam

Verse 16

तेन त५ ह बको दाल्भ्यो विदाञ्चकार ।

In plain words

Through that very means Baka Dalbhya came to know it.

Close to the Sanskrit

By that indeed Baka Dalbhya came to know it.