Shiva Purana
॥ भैरव उवाच ॥ ब्रह्मणस्तु शिरश्छिन्नमंगुल्याग्रनखेन ह ॥ तदघम्प्रतिहन्तुं हि चराम्येतद्व्रतं शुभम् ॥ २५ ॥
Bhairava said:— Brahma's head was cut off with the top of the nail of my fingers. It is to remove that sin that I am observing this auspicious sacred rite.
english translation
॥ bhairava uvAca ॥ brahmaNastu zirazchinnamaMgulyAgranakhena ha ॥ tadaghampratihantuM hi carAmyetadvrataM zubham ॥ 25 ॥
hk transliteration by Sanscript