Matsya Purana — The Madana-Dvādaśī Vow and the Birth of the Maruts
दानशीला तृतीयायां पार्वण्यं नक्तमाचरेत् इतिवृत्ता भवेन्नारी विशेषेण तु गर्भिणी //
dānaśīlā tṛtīyāyāṃ pārvaṇyaṃ naktamācaret itivṛttā bhavennārī viśeṣeṇa tu garbhiṇī //
On the third lunar day (tṛtīyā), a woman devoted to charity should observe the parvan rite by eating only at night (naktabhojana). Thus a woman becomes well-conducted in her vows—especially if she is pregnant.
This verse does not discuss pralaya; it focuses on vrata-dharma—timed ritual conduct tied to lunar days (tithi) and parvan observances.
It gives householder-style ethical and ritual guidance: charity (dāna) plus regulated eating as a discipline on specific tithis, emphasizing social-religious order that a king and householders are expected to uphold.
The significance is ritual rather than architectural: observing a parvan-related vow on tṛtīyā with night-only eating (naktam) and charitable disposition, with special care prescribed for pregnant women.