Brahmopadeśa: Adhipatitva-kathana, Dharma-lakṣaṇa, and Kṣetra–Kṣetrajña Viveka
Book 14, Chapter 43
शब्दलक्षणमाकाशं वायुस्तु स्पर्शलक्षण: । ज्योतिषां लक्षणं रूपमापश्ष रसलक्षणा:,शब्द आकाशका, वायु स्पर्शका, रूप तेजका और रस जलका लक्षण है
śabdalakṣaṇam ākāśaṁ vāyus tu sparśalakṣaṇaḥ | jyotiṣāṁ lakṣaṇaṁ rūpam āpaś ca rasalakṣaṇāḥ ||
Vāyu-deva said: “Sound is the defining mark of space (ākāśa). Touch is the defining mark of wind (vāyu). Form is the defining mark of light/fire (tejas). Taste is the defining mark of water (āpas).”
वायुदेव उवाच
Each element is recognized by its characteristic sensory quality: space by sound, wind by touch, fire/light by form, and water by taste. The verse trains discernment (viveka) by mapping the world to fundamental qualities, a step toward understanding how perception relates to the constituents of nature.
Vāyu-deva is instructing the listener in a doctrinal explanation of the elements (tattvas), presenting a concise list of defining attributes as part of a broader philosophical discourse in the Ashvamedhika Parva.