Verse 5.2.6

अथ प्रतिसृप्याञ्जलौ मन्थमाधाय जपत्यमो नामास्यमा हि ते सर्वमिदं स हि ज्येष्ठः श्रेष्ठो राजाधिपतिः स मा ज्यैष्ठ्यं श्रैष्ठ्यं राज्यमाधिपत्यं गमयत्वहमेवेदं सर्वमसानीति ॥ ५.२.६ ॥

atha pratisṛpyāñjalau manthamādhāya japatyamo nāmāsyamā hi te sarvamidaṃ sa hi jyeṣṭhaḥ śreṣṭho rājādhipatiḥ sa mā jyaiṣṭhyaṃ śraiṣṭhyaṃ rājyamādhipatyaṃ gamayatvahamevedaṃ sarvamasānīti || 5.2.6 ||

6. Then, moving some distance from the fire and holding the homa pot in his hands, he keeps repeating the mantra: ‘You are named ama, because all this rests on you. You are the first, the best, outstanding, and supreme. May I also be the first, the best, outstanding, and supreme. May I be all all this.’

Word-for-word explanation:

Atha, then; pratisṛpya, moving away [from the fire]; añjalau mantham ādhāya, holding the homa pot in his hands; japati, he keeps repeating; amaḥ nāma asi, you are named ‘ama’; amā hi te, because on you [as prāṇa]; sarvam idam, all this [rests]; saḥ hi jyeṣṭhaḥ śreṣṭhaḥ, he [i.e., prāṇa, called here ‘ama’] is the oldest and the best; rājā, princely; adhipatiḥ, supreme; saḥ, that [prāṇa]; mā gamayatu, make me; jyaiṣṭhyam śraiṣṭhyam rājyam ādhipatyam, the first, the best, outstanding, and supreme; aham eva idam sarvam asāni iti, may I be all this.

Commentary:

According to Śaṅkara, ama is another name for prāṇa.

The whole world rests on prāṇa. This is why prāṇa is also called ama (all). Prāṇa is the best and the highest. Prāṇa is this world.