Matsya Purana — The Madana-Dvādaśī Vow and the Birth of the Maruts
अनेन विधिना सर्वं मासि मासि व्रतं चरेत् उपवासी त्रयोदश्याम् अर्चयेद्विष्णुमव्ययम् //
anena vidhinā sarvaṃ māsi māsi vrataṃ caret upavāsī trayodaśyām arcayedviṣṇumavyayam //
Following this prescribed method, one should observe the vow month after month; fasting on Trayodaśī, the thirteenth lunar day, one should worship Viṣṇu, the imperishable.
This verse does not address pralaya directly; it focuses on ongoing monthly religious discipline (vrata) centered on worship of the imperishable Vishnu, implying continuity of dharma across changing times.
It prescribes a repeatable monthly vow: fasting on Trayodaśī and worshipping Vishnu. Such observances are typical householder duties and are also recommended for rulers as personal discipline supporting righteous governance.
The ritual significance is the rule-based vrata practice: observe the vow monthly, fast on Trayodaśī, and perform Vishnu-arcana (formal worship). No Vāstu or temple-construction detail is specified in this verse.