The works of Ādi Śaṅkarācārya

Chāndogyopaniṣadbhāṣyam

Bhashya

Bhashya

यो ह वै कश्चित् ज्येष्ठं च प्रथमं वयसा श्रेष्ठं च गुणै-रभ्यधिकं वेद, स ज्येष्ठश्च ह वै श्रेष्ठश्च भवति ।फलेन

In plain words

Whoever knows the one who is eldest by age and best by virtue, that person truly becomes the eldest and the best in reward.

Close to the Sanskrit

Whoever indeed knows the eldest, first in age, and the best, superior in virtues, that person indeed becomes the eldest and the best, by fruit.