niśamya nirhrādam apūrvam adbhutam
antaḥ-sabhāyāṁ na dadarśa tat-padaṁ
vitatrasur yena surāri-yūtha-pāḥ
In Bhagavad-gītā (7.8), Kṛṣṇa explains Himself by saying:
raso ’ham apsu kaunteya
prabhāsmi śaśi sūryayoḥ
śabdaḥ khe pauruṣaṁ nṛṣu
“O son of Kuntī [Arjuna], I am the taste of water, the light of the sun and the moon, the syllable om in the Vedic mantras; I am the sound in ether and ability in man.” Here the Lord exhibited His presence everywhere by the tumultuous sound in the sky (śabdaḥ khe). The tumultuous thundering sound was proof of the Lord’s presence. The demons like Hiraṇyakaśipu could now realize the supreme ruling power of the Lord, and thus Hiraṇyakaśipu became afraid. However powerful a man may be, he always fears the sound of a thunderbolt. Similarly, Hiraṇyakaśipu and all the demons who were his associates were extremely afraid because of the presence of the Supreme Lord in the form of sound, although they could not trace out the source of the sound.