The Book of Zephaniah is a book of the Bible and is thought to be written by â Zephaniah son of Cushi son of Gedaliah son of Amariah son of Hezekiah , in the days of King Josiah son of Amon of Judahâ . The superscription of the Book of Zephaniah attributes its authorship to â Zephaniah son of Cushi son of Gedaliah son of Amariah son of Hezekiah , in the days of King Josiah son of Amon of Judahâ ( 1:1 , NRSV ) .