Matsya Purana — Vrata-Ṣaṣṭhī: The Sixty Sacred Vows
आषाढादिचतुर्मासं प्रातःस्नायी भवेन्नरः विप्रेषु भोजनं दद्यात् कार्त्तिक्यां गोप्रदो भवेत् स वैष्णवं पदं याति विष्णुव्रतमिदं शुभम् //
āṣāḍhādicaturmāsaṃ prātaḥsnāyī bhavennaraḥ vipreṣu bhojanaṃ dadyāt kārttikyāṃ goprado bhavet sa vaiṣṇavaṃ padaṃ yāti viṣṇuvratamidaṃ śubham //
If a man, throughout the four months beginning with Āṣāḍha, bathes at dawn, gives food to the Brāhmaṇas, and in Kārttika donates a cow, he attains the Vaiṣṇava abode. This auspicious observance is the Viṣṇu-vrata, the vow of Viṣṇu.
This verse does not discuss Pralaya; it teaches a merit-producing Vaiṣṇava vow (Viṣṇu-vrata) centered on Cāturmāsya discipline, charity, and Kārttika go-dāna.
It presents householder-style dharma: daily purity through dawn bathing, sustaining the learned (vipras) through food-gifts, and performing go-dāna in Kārttika—actions framed as leading to the Vaiṣṇava abode.
The significance is ritual rather than architectural: Cāturmāsya observance (regulated conduct for four months), dāna to Brahmins, and the especially meritorious Kārttika cow-donation as part of a Viṣṇu-focused vrata.