The works of Ādi Śaṅkarācārya

Chāndogyopaniṣadbhāṣyam

Verse 225

मानवो ब्रह्मैवैक ऋत्विकुरूनश्वाभिर-

In plain words

The sage Manava, serving alone as the Brahman priest... protecting horses...

Close to the Sanskrit

Manava, the Brahman alone as the single officiating priest... protecting horses...