Matsya Purana — Characteristics of Dvāpara and Kali Yugas
मन्वन्तराधिकारेषु तिष्ठन्ति ऋषयस्तु ते यथा दावप्रदग्धेषु तृणेष्वेवापरं तृणम् //
manvantarādhikāreṣu tiṣṭhanti ṛṣayastu te yathā dāvapradagdheṣu tṛṇeṣvevāparaṃ tṛṇam //
In the successive jurisdictions of the Manvantaras, those sages continue to abide—just as, when grass has been scorched by a forest-fire, fresh grass again appears upon the very same ground.
It implies that even after destructive cycles (Pralaya-like devastation), the lineage and function of the rishis re-emerge in the next Manvantara, like grass growing back after a wildfire.
It underscores that dharma and sacred knowledge are preserved through rishis across ages; a king or householder should therefore support sages, protect learning, and follow time-tested dharma rather than treating social order as newly invented.
No direct Vastu or ritual rule is stated; the takeaway is the principle of continuity—ritual traditions and authoritative teachings are renewed after disruptions, guiding later rites and institutions.