The prophet Zephaniah was active in the late seventh century b.c., most likely just before 621 b.c., when the discovery of a copy of the book of Deuteronomy spurred the religious reforms carried out by the young king Josiah (640–609 b.c.). When Josiah became king in Judah he was only eight years old, and it was just two years since the long and corrupt reign of King Manasseh (687–642 b.c.), who had survived only by being a compliant vassal to Assyria. But in the years of Josiah, Assyria was preoccupied with internal power struggles and civil war (and, as they could not have known, only several decades from their demise in 612). This meant that Josiah had a brief window of freedom to make reforms and clear the temple of images and practices introduced under Assyrian pressure.
The opening verse dates the book of Zephaniah to “the days of Josiah” and then presents the prophet's first oracle in which he announces that “the day of the Lord is at hand” (1.7). When that day comes, he says, it will be a day of judgment on all who are unrighteous, including those who have been worshipping false deities, those who have adopted Assyrian ways and worship, and those who have looted and deceived for personal profit. This punishment will come to Judah, but also to other nations, especially the mighty world-power Assyria (2.13-15). In the first chapter, the day of the Lord is announced with alarming images of God's destructive power, through which all life on earth—people and animals, birds and fish—will be stricken (in the reverse order of their creation; 1.2,3). The prophet says that this severe judgment is coming soon but without warning, and that those who are righteous, who humbly obey God and worship God alone, may survive that day of reckoning. But the conclusion foresees the faithful returning to Judah and Jerusalem in jubilation.
A Day of Judgment for Judah (1.1—2.3)
A Day of Judgment for Other Nations (2.4—3.13)
A Day of Restoration Is Promised for Judah (3.14-20)