Matsya Purana — The Rohiṇī–Candraśayana Vow
इदमेव पितॄणां च सर्वदा वल्लभं मुने त्रैलोक्याधिपतिर्भूत्वा सप्तकल्पशतत्रयम् चन्द्रलोकमवाप्नोति विद्युद्भूत्वा तु मुच्यते //
idameva pitṝṇāṃ ca sarvadā vallabhaṃ mune trailokyādhipatirbhūtvā saptakalpaśatatrayam candralokamavāpnoti vidyudbhūtvā tu mucyate //
This alone is ever especially dear to the Pitṛs, O sage. Having become lord of the three worlds for three hundred and seven hundred kalpas, one attains the Moon-world; and then, becoming like lightning, one is released—attaining mokṣa.
It does not describe pralaya directly; it teaches karmic and post-mortem results of Pitṛ-pleasing rites—first exalted sovereignty and heavenly enjoyment (Candra-loka), culminating in release (mukti).
It reinforces the gṛhastha/kingly duty of honoring ancestors through prescribed rites, presenting Pitṛ-satisfaction as a dharmic act that yields long-lasting merit, status, and ultimately spiritual freedom.
The focus is ritual (Śrāddha/Pitṛ offerings): the verse functions as phalaśruti, stressing that this specific Pitṛ-priya act is exceptionally effective, promising Candra-loka and eventual mokṣa.