Matsya Purana — Agastya’s Origin
मित्रावरुणयोर्वीर्याद् वसिष्ठस्यानुजो ऽभवत् अगस्त्य इत्युग्रतपाः संबभूव पुनर्मुनिः //
mitrāvaruṇayorvīryād vasiṣṭhasyānujo 'bhavat agastya ityugratapāḥ saṃbabhūva punarmuniḥ //
From the virile potency of Mitra and Varuṇa there arose a younger brother of Vasiṣṭha; that sage, renowned for fierce austerities, was born again as the muni called Agastya.
This verse is not about Pralaya; it preserves a genealogical-cosmogonic tradition explaining the origin of a great rishi (Agastya) from the divine potency of Mitra and Varuṇa.
Indirectly, it supports dharmic culture by grounding royal and social ethics in reverence for rishis: kings and householders are urged in Purāṇic frameworks to honor such seers, uphold ritual order, and protect the institutions of tapas and learning.
No Vāstu/temple-rule is stated here; the ritual takeaway is the Purāṇic emphasis on tapas (austerity) and rishi-authority as foundations for correct rites and tradition.