Shiva Purana
कृत्यमित्येव निष्कामो यश्चरेद्व्रतमुत्तमम् ॥ शिवार्पितात्मा सततं न तेन सदृशः क्वचित् ॥ ८९ ॥
He who performs the excellent Vrata without a desire for the fruit feeling that it is his duty, always dedicating his Arman to Śiva has no one equal to him.
english translation
kRtyamityeva niSkAmo yazcaredvratamuttamam ॥ zivArpitAtmA satataM na tena sadRzaH kvacit ॥ 89 ॥
hk transliteration by Sanscript