Matsyapurana 74.15

74.15

prīyatāmatra bhagavān paramātmā divākaraḥ
anena vidhinā sarvaṃ māsi māsi vrataṃ caret //

At that time the devotee should say: "O, Adorable Sun, the Supreme Self, be pleased." The worship of the Sun should thus be followed for a year, on the bright Saptamî of every month, and in the 13th month, 13 cows, with their mouths covered with gold and bodies adorned with clothes and ornaments, should be given away.—15-16.