Matsya Purana — The Rite and Glory of Meru-Dāna: The Tenfold ‘Gift of Meru’ and Mountain-Offe...
अनेन विधिना यस्तु दद्याद्धान्यमयं गिरिम् मन्वन्तरशतं साग्रं देवलोके महीयते //
anena vidhinā yastu dadyāddhānyamayaṃ girim manvantaraśataṃ sāgraṃ devaloke mahīyate //
Whoever, in accordance with this prescribed rite, donates a “mountain” made of grain is honored in the world of the gods for a full hundred Manvantaras and even beyond.
It does not describe Pralaya directly; it uses the cosmic time-unit “Manvantara” to express the vast duration of merit gained through a properly performed donation.
It frames charity (especially grain-giving, a life-sustaining gift) as a prime duty of householders and rulers, promising enduring heavenly honor when the gift is done according to correct ritual procedure.
The key ritual point is “anena vidhinā”—the donation must follow an established विधि; the specific act is constructing a symbolic ‘mountain’ heap of grain (dhānyamaya giri) as a formal dāna offering.