The superscription of the Book of Zephaniah attributes its authorship to "Zephaniah son of Cushi son of Gedaliah son of Amariah son of Hezekiah, in the days of King Josiah son of Amon of Judah" (1:1, NRSV). All that is known of Zephaniah comes from the text. The superscription of the book is lengthier than most and contains two features. The name Cushi, Zephaniah's father, means 'Ethiopian'. In a society where genealogy was considered extremely important because of God's covenant with Abraham and his descendants, the author may have felt compelled to establish his Hebrew lineage. In fact, this lineage is traced back to Hezekiah, who was king of Judah. The author of Zephaniah does not shrink from condemning the Cushites or Ethiopians. Chapter 2:12 contains a succinct but unequivocal message: "You also, O Ethiopians, / Shall be killed by my sword." Zephaniah's familial connection with King Hezekiah may have also legitimized his harsh indictment of the royal city in 3:1-7. (Summary by Wikipedia)