The works of Ādi Śaṅkarācārya

Chāndogyopaniṣadbhāṣyam

Verse 227

यो ह वै ज्येष्ठं च श्रेष्ठं च वेद ज्येष्ठश्चह वै श्रेष्ठश्च भवति प्राणो वाव ज्येष्ठश्चश्रेष्ठश्च ॥ १ ॥

In plain words

Whoever truly knows the oldest and the best becomes the oldest and the best themselves. Verily, prāṇa is that oldest and best.

Close to the Sanskrit

He who indeed and truly knows the eldest and the best, he indeed becomes the eldest and the best. Prāṇa verily is the eldest and the best.