Śvetāśvatara Upaniṣad · 1..8
भयादस्याग्निस्तपति भयात्तपति सूर्यः भयादिन्द्रश्च वायुश्च मृत्युर्धावति पञ्चमः
bhayādasyāgnistapati bhayāttapati sūryaḥ bhayādindraśca vāyuśca mṛtyurdhāvati pañcamaḥ
Out of fear of Him burns the fire, out of fear of Him shines the sun, out of fear of Him run Indra, the wind and death as the fifth.
This apparently fearful image actually describes cosmic dependence. The “fear” (bhaya) here is reverence, the natural obedience of forces to supreme law. Neither fire, nor sun, nor the gods Indra and Vāyu, nor even Mṛtyu (death personified) act by their own will, but fulfill their function in obedience to Brahman. In our yoga practice, this reminds us that even our bodily functions — breathing, heartbeat, digestion — are not automatic but sustained by a divine Presence. Recognizing this dependence is the foundation of humility and gratitude.