Srimad Bhagavatam Canto 01, Chapter 06, Text 25

SB 1.6.25

etavad uktvopararama tan mahad
bhutam nabho-lingam alingam isvaram
aham ca tasmai mahatam mahiyase
sirsnavanamam vidadhe ’nukampitah
 
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada: 
 
Then that supreme authority, personified by sound and unseen by eyes, but most wonderful, stopped speaking. Feeling a sense of gratitude, I offered my obeisances unto Him, bowing my head.
 
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada: 
 
That the Personality of Godhead was not seen but only heard does not make any difference. The Personality of Godhead produced the four Vedas by His breathing, and He is seen and realized through the transcendental sound of the Vedas. Similarly, the Bhagavad-gita is the sound representation of the Lord, and there is no difference in identity. The conclusion is that the Lord can be seen and heard by persistent chanting of the transcendental sound.
Srimad Bhagavatam Canto 01, Chapter 06, Text 24
Srimad Bhagavatam Canto 01, Chapter 06, Text 26