Matsya Purana — Catalogue of the Eighteen Puranas
आश्विने पञ्चदश्यां तु दद्याद्धेनुसमन्वितम् परमां सिद्धिमाप्नोति पुनरावृत्तिदुर्लभाम् //
āśvine pañcadaśyāṃ tu dadyāddhenusamanvitam paramāṃ siddhimāpnoti punarāvṛttidurlabhām //
On the fifteenth lunar day of the month of Āśvina, one should give a gift accompanied by a cow; by this, one attains the highest spiritual perfection, after which return to worldly rebirth is rare.
It does not describe Pralaya directly; it teaches that properly timed charity (dāna) can lead to supreme attainment and release from repeated return (punarāvṛtti), a soteriological theme often linked to liberation beyond cosmic cycles.
It frames a householder/kingly duty as charitable giving on an auspicious tithi—specifically a gift that includes a cow—presented as a dharmic act yielding high spiritual fruit and supporting social-religious welfare.
The significance is ritual (not architectural): it prescribes a tithi-specific dāna in Āśvina pañcadaśī and highlights go-dāna as a potent rite associated with supreme spiritual accomplishment.