Matsya Purana — Devayānī Meets Yayāti: Courtship
*ययातिरुवाच एकदेहोद्भवा वर्णाश् चत्वारो ऽपि वरानने पृथग्धर्माः पृथक्छौचास् तेषां वै ब्राह्मणो वरः //
*yayātiruvāca ekadehodbhavā varṇāś catvāro 'pi varānane pṛthagdharmāḥ pṛthakchaucās teṣāṃ vai brāhmaṇo varaḥ //
Yayāti said: “O fair-faced one, though the four varṇas arise from a single body, their duties are distinct and their standards of purity are distinct; among them, indeed, the Brāhmaṇa is the foremost.”
This verse does not address Pralaya; it teaches social order—how four varṇas, though originating from a single source, are differentiated by distinct dharmas and purity disciplines.
It frames governance and household ethics around varṇa-specific duties and standards of conduct; a king (and householders) should uphold social harmony by recognizing differentiated roles and maintaining appropriate standards of śauca (purity/discipline) for each.
No Vāstu or temple-architecture rule is stated here; the ritual implication is the emphasis on śauca—distinct purity disciplines that guide eligibility and propriety in rites across varṇas.