Matsya Purana — Manvantaras
ऋचो यजूंषि सामानि ब्रह्मणो ऽङ्गानि वै श्रुतिः मन्वन्तरस्यातीतस्य स्मृत्वा तन्मनुरब्रवीत् //
ṛco yajūṃṣi sāmāni brahmaṇo 'ṅgāni vai śrutiḥ manvantarasyātītasya smṛtvā tanmanurabravīt //
The Ṛk, Yajus, and Sāman—indeed the Veda (Śruti)—are the very limbs of Brahmā. Remembering the manvantara that had passed, that Manu then spoke.
It implies continuity of revealed knowledge across cosmic cycles: even after a manvantara has passed, Manu “remembers” the Veda (Śruti), described as Brahmā’s limbs—suggesting Vedic order persists through dissolution and renewal.
By grounding Manu’s speech in Śruti, the verse signals that dharma—whether royal governance or household conduct—should be derived from Vedic authority, not mere personal preference.
While not naming Vāstu directly, it establishes Śruti as foundational authority; in the Matsya Purāṇa’s ritual and temple-building rules, such prescriptions are traditionally justified as flowing from Vedic revelation.