Matsya Purana — Solar–Lunar Motions
अतः परं ह्रसन्तीभिर् गोभिरस्तं स गच्छति उदयास्तमयाभ्यां च स्मृते पूर्वापरे तु वै //
ataḥ paraṃ hrasantībhir gobhirastaṃ sa gacchati udayāstamayābhyāṃ ca smṛte pūrvāpare tu vai //
Thereafter, by the “cows” that diminish—namely, the waning rays—he is understood to be going toward setting. And by sunrise and sunset, the two directions, east and west, are indeed recognized as before and after.
This verse is not about pralaya; it focuses on practical cosmological reckoning—how to recognize sunset and how sunrise/sunset establish the east–west axis used in sacred time and space.
It supports dharma through correct daily and ritual timing: knowing sunrise/sunset and east/west helps a householder schedule sandhyā and rites, and helps a king regulate public rituals, vows, and auspicious commencements.
Sunrise and sunset define pūrva–apara (east–west), a key orientation principle for altars, temples, and house-plots; correct directional knowledge is foundational for Vastu-alignment and for performing rites facing the proper direction.