Matsya Purana — The Attendant Hosts of the Sun and Moon: Monthly Gaṇas
वालखिल्या नयन्त्यस्तं परिवार्योदयाद्रविम् एतेषामेव देवानां यथावीर्यं यथातपः //
vālakhilyā nayantyastaṃ parivāryodayādravim eteṣāmeva devānāṃ yathāvīryaṃ yathātapaḥ //
The Vālakhilyas, surrounding the Sun from his rising onward, lead him to his setting. Thus, among these divine beings, each performs according to his own power and ascetic heat (tapas).
It does not describe Pralaya directly; it emphasizes cosmic order—how the Sun’s daily movement is upheld by divine/ascetic beings acting through tapas.
By analogy, it teaches svadharma: just as celestial beings perform according to their capacity and discipline, a king or householder should uphold order through steady duty, proportionate effort, and self-restraint.
No Vāstu rule is stated explicitly, but the verse supports solar-oriented ritual logic (udaya/asta): many rites, temple schedules, and auspicious timings are anchored to sunrise and sunset in Purāṇic practice.