Matsya Purana — Manvantaras
ब्रह्मणो मानसा ह्येते उत्पन्नाः स्वयमीश्वराः परत्वेनर्षयो यस्मान् मतास्तस्मान्महर्षयः //
brahmaṇo mānasā hyete utpannāḥ svayamīśvarāḥ paratvenarṣayo yasmān matāstasmānmaharṣayaḥ //
These sages were indeed mind-born from Brahmā, self-possessed and lordly in their own right. Since they are regarded as foremost among the ṛṣis, therefore they are called the Mahārṣis (Great Sages).
It clarifies a creation principle: certain prime sages are described as Brahmā’s “mind-born” progeny, indicating non-physical, will-based origination within cosmic creation cycles (not a pralaya event itself).
By establishing the Mahārṣis as the highest authoritative seers, it implies that kings and householders should ground dharma, law, and ritual practice in teachings transmitted through such sage lineages.
No direct Vāstu or iconographic rule is stated; the ritual takeaway is authority—ritual standards are to be followed as taught by the foremost ṛṣis (Mahārṣis) recognized in the tradition.