Verse 3.5.1

अथ येऽस्योर्ध्वा रश्मयस्ता एवास्योर्ध्वा मधुनाड्यो गुह्या एवादेशा मधुकृतो ब्रह्मैव पुष्पं ता अमृता आपः ॥ ३.५.१ ॥

atha ye'syordhvā raśmayastā evāsyordhvā madhunāḍyo guhyā evādeśā madhukṛto brahmaiva puṣpaṃ tā amṛtā āpaḥ || 3.5.1 ||

1. Next, the rays of the sun which are in the higher region are also its honey-cells in the higher region. The secret instructions are the bees, and Brahman [praṇava] is the flower. The water [from the sacrifice] is the nectar.

Word-for-word explanation:

Atha, next; asya ye urdhvāḥ raśmayaḥ, those rays [of the sun] which are in the higher region; tāḥ eva asya urdhvāḥ madhunāḍyaḥ, they are its honeycomb in the higher region; guhyāḥ ādeśāḥ eva madhukṛtaḥ, all secret directions are the bees; brahma eva puṣpam, Brahman [i.e., praṇava, Om] is the flower; tāḥ āpaḥ amṛtāḥ, the water [used in this connection] is the nectar.

Commentary:

The mantras used in the sacrifices are both secret and mystical. So also are the directions for a successful performance of a sacrifice. The mantras and the directions together constitute the bees in the illustration given here. The word brahman is used here in the sense of ‘word,’ so it means here praṇava, or Om. It is the flower.