Verse 5.1.1

॥ पञ्चमोऽध्यायः ॥
यो ह वै ज्येष्ठं च श्रेष्ठं च वेद ज्येष्ठश्च ह वै श्रेष्ठश्च भवति प्राणो वाव ज्येष्ठश्च श्रेष्ठश्च ॥ ५.१.१ ॥

|| pañcamo'dhyāyaḥ ||
yo ha vai jyeṣṭhaṃ ca śreṣṭhaṃ ca veda jyeṣṭhaśca ha vai śreṣṭhaśca bhavati prāṇo vāva jyeṣṭhaśca śreṣṭhaśca || 5.1.1 ||

1. Om. He who knows the oldest and the best himself becomes the oldest and the best. It is prāṇa which is the oldest and the best.

Word-for-word explanation:

Yaḥ ha vai, he who; jyeṣṭham ca śreṣṭham ca veda, knows the oldest and the best; jyeṣṭhaḥ ca ha vai śreṣṭhaḥ ca bhavati, himself becomes the oldest and the best; prāṇaḥ vāva jyeṣṭhaḥ ca śreṣṭhaḥ ca, prāṇa is indeed the oldest and the best.

Commentary:

The importance of prāṇa has been mentioned earlier. True, it works in conjunction with the organs of speaking, hearing, seeing, etc., but it is the first and foremost of all of them. Prāṇa is in a child even when it is still in it’s mother’s womb. It is active before the various organs are active. Prāṇa therefore commands respect from all.

The reason why so much importance is given to prāṇa is to teach us to show respect where respect is due. We should respect both age and merit. Then we also shall command respect from all because of our age and merit. Indirectly, this is a hint that we should respect knowledge.