CHĀNDOGYA UPANISHAD · 3.2.1

अथ ये ऽस्य दक्षिणा रश्मयस् ता एवास्य दक्षिणा मधुनाड्यः ।
यजूंष्य् एव मधुकृतः ।
यजुर्वेद एव पुष्पम् ।
ता अमृता आपः ॥

atha ye ’sya dakṣiṇā raśmayas tā evāsya dakṣiṇā madhunāḍyaḥ ।
yajūṃṣy eva madhukṛtaḥ ।
yajurveda eva puṣpam ।
tā amṛtā āpaḥ ॥

The southern rays of the sun are the honey-cells on the right. The Yagus verses are the bees, the Yagur-veda sacrifice is the flower, the water (of the sacrificial libations) is the nectar (of the flower).

F. Max Müller · The Upanishads, Sacred Books of the East 1 (1879)