Matsya Purana — Measures of Time: Caturyuga Computation
ऋचो यजूंषि सामानि मन्त्राश्चाथर्वणास्तु ये सप्तर्षिभिश्च ये प्रोक्ताः स्मार्तं तु मनुरब्रवीत् //
ṛco yajūṃṣi sāmāni mantrāścātharvaṇāstu ye saptarṣibhiśca ye proktāḥ smārtaṃ tu manurabravīt //
The Ṛk-verses, the Yajus-formulas, the Sāman-chants, and the Atharvan-mantras—together with the teachings declared by the Seven Sages—these Manu proclaimed as the authoritative tradition of Smārta dharma.
Nothing directly about pralaya is stated here; the verse instead defines scriptural authority—Vedic mantras and Saptarṣi teachings—as the basis for Smārta dharma.
It grounds conduct in recognized sources: household and royal rituals, vows, and legal norms should align with Vedic mantras and the Saptarṣis’ transmitted teachings as systematized by Manu (i.e., Smārta dharma).
Ritually, it affirms that procedures and recitations draw legitimacy from the four Vedas and sage-traditions—an important rule when selecting mantras for consecrations, homa, and other samskāras (including temple-related rites).