Matsya Purana — Narasimha’s Victory over Hiraṇyakaśipu and the Catalogue of Apocalyptic Omens
तमसा संवृते लोके दैत्येष्वात्तायुधेषु च स्वतेजसा परिवृतो दिवाकर इवाबभौ //
tamasā saṃvṛte loke daityeṣvāttāyudheṣu ca svatejasā parivṛto divākara ivābabhau //
When the world was shrouded in darkness and the Daityas had seized their weapons, he—encircled by his own radiance—shone forth like the Sun.
It does not describe Pralaya directly; it uses darkness (tamas) as a battlefield/cosmic motif, contrasting it with a figure whose innate radiance dispels gloom like the Sun.
By portraying steadfast brilliance amid armed hostility, it aligns with the royal virtue of tejas (moral-spiritual power and courage): a ruler should remain composed and illuminating in crises rather than succumb to fear or confusion.
No explicit Vastu or ritual procedure is mentioned; the primary significance is symbolic—light (divākara/tejas) as auspicious power that overcomes tamas, a theme often echoed in ritual contexts.