Matsya Purana — Vrata-Ṣaṣṭhī: The Sixty Sacred Vows
तद्वद्धेमरथं दद्यात् करिभ्यां संयुतं नरः सत्यलोके वसेत्कल्पं सहस्रमथ भूपतिः भवेदुपोषितो भूत्वा करिव्रतमिदं स्मृतम् //
tadvaddhemarathaṃ dadyāt karibhyāṃ saṃyutaṃ naraḥ satyaloke vasetkalpaṃ sahasramatha bhūpatiḥ bhavedupoṣito bhūtvā karivratamidaṃ smṛtam //
Likewise, a man should donate a golden chariot yoked with two elephants. Thereafter he dwells in Satyaloka for a thousand kalpas, and he becomes a king. Having observed fasting, this is declared to be the Elephant-vow (Kari-vrata).
It does not describe Pralaya directly; it reflects the Purana’s karmic cosmology where specific gifts and vows yield posthumous residence in higher worlds such as Satyaloka (Brahmaloka), a realm associated with Brahmā’s cosmic cycle (kalpa).
It frames dāna (charitable gifting) and upavāsa (fasting) as core dharma for householders and rulers: by sponsoring an exalted gift (a golden chariot with elephants) and observing the vow, one accrues merit leading to sovereignty (bhūpati) and elevated heavenly attainment.
The ritual significance is primarily vrata–dāna procedure: a prescribed donation (golden chariot with two elephants) linked to a named vow (kari-vrata) and its phala (Satyaloka residence and kingship), rather than Vāstu or temple-construction rules.