Matsya Purana — Origin of Soma
वेदधामरसं चापि यदिदं चन्द्रमण्डलम् क्षीयते वर्धते चैव शुक्ले कृष्णे च सर्वदा //
vedadhāmarasaṃ cāpi yadidaṃ candramaṇḍalam kṣīyate vardhate caiva śukle kṛṣṇe ca sarvadā //
This lunar orb, which is also said to be the essence of the Veda and the abode of sacred radiance, continually wanes and waxes—ever in the bright fortnight and the dark fortnight.
It does not describe Pralaya directly; it emphasizes the steady cosmic rhythm of the Moon’s waxing and waning as a maintained order within creation.
By foregrounding Śukla- and Kṛṣṇa-pakṣa, it supports dharmic timekeeping: household rites, vratas, śrāddha timing, and royal calendrical administration aligned with the lunar fortnight system.
Ritually, it underlines lunar-fortnight scheduling for ceremonies; architecturally, it implies (indirectly) the importance of calendrical auspicious timing (muhūrta) rather than giving specific Vastu rules in this verse.