Matsya Purana — The Rite of the Vibhūti-Dvādaśī Vow
तदविघ्नेन मे यातु सफलं स्याच्च केशव नमो नारायणायेति वाच्यं च स्वपता निशि //
tadavighnena me yātu saphalaṃ syācca keśava namo nārāyaṇāyeti vācyaṃ ca svapatā niśi //
May that undertaking proceed for me without obstacles and become fruitful in success. O Keśava—even while sleeping at night, one should utter: “Namo Nārāyaṇāya.”
This verse does not discuss pralaya; it teaches a practical devotional method—invoking Nārāyaṇa—to ensure one’s actions proceed without obstacles and reach success.
It presents a simple dhārmic discipline: constant remembrance of Nārāyaṇa (even at night) to secure auspiciousness and remove impediments—useful for householders and rulers alike when beginning or sustaining duties.
No vastu/temple-measurement rule appears here; the ritual takeaway is japa/uccāraṇa of the mantra “Namo Nārāyaṇāya” as an apotropaic (obstacle-removing) practice.