अस्तमित आदित्ये याज्ञवल्क्य, चन्द्रमस्यस्तमिते, शान्तेऽग्नौ किंज्योतिरेवायं पुरुष इति; वागेवास्य ज्योतिर्भवतीति, वाचैवायं ज्योतिषास्ते पल्ययते कर्म कुरुते विपल्येतीति; तस्माद्वै सम्राडपि यत्र स्वः पाणिर्न विनिर्ज्ञायते, अथ यत्र वागुच्चरति, उपैव तत्र न्येतीति; एवमेवैतद्याज्ञवल्क्य ॥ ५ ॥
astamita āditye yājñavalkya, candramasyastamite, śānte’gnau kiṃjyotirevāyaṃ puruṣa iti; vāgevāsya jyotirbhavatīti, vācaivāyaṃ jyotiṣāste palyayate karma kurute vipalyetīti; tasmādvai samrāḍapi yatra svaḥ pāṇirna vinirjñāyate, atha yatra vāguccarati, upaiva tatra nyetīti; evamevaitadyājñavalkya || 5 ||
5. ‘When the sun and the moon have both set, and the fire has gone out, Yājñavalkya, what serves as the light for a man?’ ‘Speech (sound) serves as his light. It is through the light of speech that he sits, goes out, works and returns. Therefore, O Emperor, even when one’s own hand is not clearly visible, if a sound is uttered, one manages to go there.’ ‘Just so, Yājñavalkya.’
When the fire has gone out, speech serves as the light. ‘Speech’ here means sound. Sound, which is the object of hearing, stimulates the ear, its organ; this gives rise to discrimination in the mind; through that mind a man engages in an outward action. Elsewhere it has been said, ‘It is through the mind that one sees and hears’ (I. v. 3). How can speech be called a light, for it is not known to be such? The answer is being given: ‘Therefore, O Emperor,’ etc. Because a man lives and moves in the world helped by the light of speech, therefore it is a well-known fact that speech serves as a light. How? ‘Even when, as in the rainy season, owing to the darkness created by clduds generally blotting out all light, one’s own hand is not clearly visible,—though every activity is then stopped owing to the want of external light—if a sound is uttered, as for instance a dog barks or an ass brays, one manages to go there. That sound acts as a light and connects the ear with the mind; thus speech (sound) does the function of a light there; With the help of that sound serving as a light, the man actually goes there, works at that place and returns.’ The mention of the light of speech includes odour etc. For when odour and the rest also help the nose and other organs, a man is induced to act or dissuaded from it, and so on. So they too help the body and organs. ‘Just so, Yājñavalkya.’