Matsya Purana — The Madana-Dvādaśī Vow and the Birth of the Maruts
ब्राह्मणान्भोजयेद्भक्त्या स्वयं च लवणादृते भुक्त्या तु दक्षिणां दद्याद् इमं मन्त्रमुदीरयेत् //
brāhmaṇānbhojayedbhaktyā svayaṃ ca lavaṇādṛte bhuktyā tu dakṣiṇāṃ dadyād imaṃ mantramudīrayet //
One should feed the brāhmaṇas with devotion, and oneself should eat without salt. After the meal, one should give the dakṣiṇā (priestly fee) and then recite this mantra.
This verse does not discuss pralaya; it focuses on dharma—proper ritual hospitality, self-restraint, and giving dakṣiṇā after feeding Brāhmaṇas.
It lays out a practical duty of the gṛhastha (and also a king as patron): feed Brāhmaṇas with devotion, practice austerity by avoiding salt oneself, and conclude the rite by giving dakṣiṇā and reciting the prescribed mantra.
The significance is ritual, not architectural: it specifies the sequence of brāhmaṇa-bhojana, personal dietary restraint (no salt), and the concluding act of dakṣiṇā accompanied by mantra-recitation.