Matsya Purana 58.53

58.53

caturthī karma kartavyaṃ deyā tatrāpi śaktitaḥ.
dakṣiṇā rājaśārdūla! varuṇakṣmāpanaṃ tataḥ.. 58.48 ..

At the end of these ceremonies the Chaturthî-Karma should be performed, when the worshipper should give dakṣiṇâ to the Brâhmaṇas, according to his means, and should mutter mantras of Varuṇa.—48.