PURPORT

"O son of Kunti [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 (sabdah khe). The tumultuous thundering sound was proof of the Lord's presence. The demons like Hiranyakasipu could now realize the supreme ruling power of the Lord, and thus Hiranyakasipu became afraid. However powerful a man may be, he always fears the sound of a thunderbolt. Similarly, Hiranyakasipu 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.