Matsya Purana — The Maheshvara Vow: Śiva-Caturdaśī Vrata
प्रीयतां देवदेवो ऽत्र सद्योजातः पिनाकधृक् ततो विप्रान्समाहूय तर्पयेद्भक्तितः शुभान् पृषदाज्यं च संप्राश्य स्वपेद्भूमावुदङ्मुखः //
prīyatāṃ devadevo 'tra sadyojātaḥ pinākadhṛk tato viprānsamāhūya tarpayedbhaktitaḥ śubhān pṛṣadājyaṃ ca saṃprāśya svapedbhūmāvudaṅmukhaḥ //
“May the God of gods—Sadyōjāta, the bearer of the Pināka—be pleased here.” Then, having summoned auspicious brāhmaṇas, one should honour and satisfy them with devotion. Having also partaken of pṛṣadājya (a ghee preparation), one should sleep upon the ground, facing north.
This verse is not about pralaya; it prescribes a ritual observance—propitiating Śiva (Sadyōjāta), honouring brāhmaṇas, and adopting an austerity (sleeping on the ground).
It frames dharmic conduct as devotional worship plus social-religious duty: inviting worthy brāhmaṇas, respectfully satisfying them, observing dietary restraint, and practising humility through simple sleeping arrangements.
The significance is ritual (not architectural): tarpaṇa/feeding of brāhmaṇas, consuming a prescribed ghee-preparation (pṛṣadājya), and the directional rule of sleeping north-facing as part of the observance.