Brahmopadeśa: Adhipatitva-kathana, Dharma-lakṣaṇa, and Kṣetra–Kṣetrajña Viveka
Book 14, Chapter 43
आकाश स्य गुणो होष श्रोत्रेण च स गृहाते । श्रोत्रस्थाश्व दिश: सर्वा: शब्दज्ञाने प्रकीर्तिता:,आकाशके गुण शब्दका कानोंके द्वारा ग्रहण होता है और कानमें स्थित सम्पूर्ण दिशाएँ शब्दके श्रवणमें सहायक बतायी गयी हैं
ākāśasya guṇo ghoṣaḥ śrotreṇa ca sa gṛhyate | śrotrasthāś ca diśaḥ sarvāḥ śabdajñāne prakīrtitāḥ ||
Vāyu-deva said: “The distinctive quality of space (ākāśa) is sound, and it is apprehended through the ear. All the directions, abiding in the organ of hearing, are said to assist the cognition of sound.”
वायुदेव उवाच
The verse states a classical tattva-doctrine: each subtle element has a defining quality, and for ākāśa (space/ether) that defining quality is śabda (sound). Sound is known through the śrotra (ear), and the ‘directions’ are poetically/physiologically linked with hearing as supportive conditions for auditory cognition.
Vāyu-deva is instructing the listener in a philosophical explanation of perception and the elements, describing how sound belongs to ākāśa and how the ear functions as the instrument by which that quality is apprehended.