Matsya Purana — Manvantaras
मन्त्राः प्रादुर्भवन्त्यादौ पूर्वमन्वन्तरस्य ह असंतोषाद्भयाद्दुःखान् मोहाच्छोकाच्च पञ्चधा //
mantrāḥ prādurbhavantyādau pūrvamanvantarasya ha asaṃtoṣādbhayādduḥkhān mohācchokācca pañcadhā //
At the very beginning of the former Manvantara, the mantras manifest in a fivefold manner—arising from discontent, fear, suffering, delusion, and grief.
It points to a Manvantara-level cosmology where mantras are said to manifest at the beginning of an epoch, linked to five inner disturbances; it is about cyclical emergence of sacred speech rather than a direct description of Pralaya itself.
By identifying discontent, fear, suffering, delusion, and grief as key destabilizers, it implies that a ruler or householder should cultivate steadiness and dharma-based discipline; mantras function as tools to pacify these states and restore order in mind and society.
The verse is primarily ritual-psychological: it frames mantras as arising in relation to mental afflictions, supporting their use in japa, homa, and expiatory rites, though it does not give direct Vastu or temple-construction rules.