Matsya Purana — The Greatness of Prayaga and the Supremacy of Cow-Donation
यावद्रोमाणि तस्या गोः सन्ति गात्रेषु सत्तम तावद्वर्षसहस्राणि स्वर्गलोके महीयते //
yāvadromāṇi tasyā goḥ santi gātreṣu sattama tāvadvarṣasahasrāṇi svargaloke mahīyate //
O best of the virtuous: for as many hairs as are upon the limbs of that cow, for that many thousands of years the donor is honored and exalted in the heavenly world.
This verse does not address Pralaya; it teaches dāna-dharma, stating the heavenly reward gained through the gift of a cow.
It supports the householder/kingly duty of dāna (charitable giving): go-dāna is presented as a highly meritorious act that yields prolonged honor in Svarga, encouraging rulers and householders to sustain society through righteous generosity.
No vāstu or temple-architecture rule appears here; the ritual significance is the phala-śruti of go-dāna—quantifying its merit as thousands of years in heaven proportional to the cow’s hairs.