Matsya Purana — The Greatness of Prayāga
मातरं पितरं चैव ये निन्दन्ति नराधमाः न तेषामूर्ध्वगमनम् इदमाह प्रजापतिः //
mātaraṃ pitaraṃ caiva ye nindanti narādhamāḥ na teṣāmūrdhvagamanam idamāha prajāpatiḥ //
Those vilest of men who revile their mother and father do not attain the upward path (the higher realms). Thus has Prajāpati declared.
This verse does not address Pralaya directly; it teaches moral causality—dishonor toward parents blocks “ūrdhvagati,” the higher post-death course, emphasizing ethical law rather than cosmology.
It reinforces foundational dharma: reverence to parents is a core householder duty, and a king is expected to uphold such social ethics through education, example, and just governance that protects family-based virtues.
No Vāstu or iconographic rule is stated here; the ritual takeaway is ethical eligibility—proper conduct toward parents is treated as a prerequisite for auspicious spiritual progress and merit-bearing rites.