Matsyapurana 101.54

101.54

pakṣopavāsī yo dadyād viprāya kapilādvayam
brahmalokamavāpnoti devāsurasupūjitam
kalpānte rājarājaḥ syāt prabhāvratamidaṃ smṛtam //

One who gives a pair of tawny colour cows (kapilâ) to a Brâhmaṇa, after fasting for a fortnight, goes to the Brahmaloka honoured by Devas and Asuras, and at the end of the kalpa becomes the monarch of kings. This is (33) Prabhâ-Vrata.—54.