Revākhaṇḍa ascribed to the Vāyupurāṇa (RKV) 75.4

75.4

rātrau jāgaraṇaṃ kuryād devasyāgre narādhipa /
dadhibhaktena sampūjya brāhmaṇāñchaṃsitavratān /
gopradāne dvijendro 'yaṃ sarvapāpakṣayaṃkaraḥ //

and keeps vigil at night before the god, O king of men, / after worshipping Brāhmaṇas of commendable vows with curd-rice— / when a gift of a cow is given to this best of the twice-born, it causes the destruction of all sins.