Matsya Purana — The Viśokā-Saptamī Vow
यावज्जन्मसहस्राणां साग्रं कोटिशतं भवेत् तावन्न शोकमभ्येति रोगदौर्गत्यवर्जितः //
yāvajjanmasahasrāṇāṃ sāgraṃ koṭiśataṃ bhavet tāvanna śokamabhyeti rogadaurgatyavarjitaḥ //
For as long as a hundred koṭis and more of thousands of births, one does not fall into sorrow, remaining free from disease and misfortune.
This verse does not discuss Pralaya directly; it is a merit-statement (phala-śruti) promising long-lasting freedom from grief, disease, and misfortune as a result of dharmic practice.
It reinforces the Matsya Purana’s ethical logic that sustained dharma—through vows, gifts, worship, and right conduct—yields tangible welfare: protection from calamity, health, and stability, which are core aims for both rulers and householders.
No explicit Vāstu/temple-building rule appears in this line; its ritual relevance is as a phala-śruti formula commonly attached to rites, indicating the protective and health-bestowing fruits of the prescribed observance.