Matsya Purana — The Sarasvata Vrata: Vow for Sweet Speech
संध्यायां च तथा मौनम् एतत्कुर्वन्समाचरेत् नान्तरा भोजनं कुर्याद् यावन्मासास्त्रयोदश //
saṃdhyāyāṃ ca tathā maunam etatkurvansamācaret nāntarā bhojanaṃ kuryād yāvanmāsāstrayodaśa //
At the times of sandhyā—the daily twilight worship—he should also observe silence; practicing these disciplines, he should live accordingly. He should not eat between meals for as long as thirteen months.
This verse does not address pralaya or cosmology; it focuses on vrata-discipline—sandhyā observance, mauna, and regulated eating over a fixed period.
It prescribes self-restraint and daily religious discipline (sandhyā and mauna) along with controlled diet—practices that a householder (and a king as a model of dharma) can adopt to cultivate steadiness, purity, and rule-based living.
The significance is ritual rather than architectural: it emphasizes sandhyā practice, the vow of silence, and a strict rule against eating between meals for thirteen months—key elements in Matsya Purana-style vrata observance.