Skandapurana 5.92.21

5.92.21

dṛṣṭvā pitāmahaṃ devaṃ pūjayitvā janārdanam ..
sa bhaviṣyati śūdro'pi brāhmaṇaścānyajanmani .. 21 ..

having seen God Pitāmaha and worshipped Janārdana, / will become a brahmin in another birth, even if he were a śūdra.”