Ganaka Vaideha said: `When the sun has set, O Yagnavalkya, and the moon has set, and the fire is gone out, what is then the light of man?' Yagnavalkya replied: `Sound indeed is his light; for, having sound alone for his light, man sits, moves about, does his work, and returns. Therefore, O King, when one cannot see even one's own hand, yet when a sound is raised, one goes towards it.' Ganaka Vaideha said: `So indeed it is, O Yagnavalkya.'