[Israel's Migration After Captivity Map]
Rare Title
Zephaniah contains a rare title applied to the Lord.
The LORD hath taken away thy judgments, he hath cast out thine enemy: the king of Israel, even the LORD, is in the midst of thee . . . (Zephaniah 3:15).
[Biblical Titles Given to Jesus]
The title "king of Israel" for God is only found in Zephaniah 3 and John 1!
Nathanael answered and saith unto him (Jesus), Rabbi, thou art the Son of God; thou art the King of Israel (John 1:49).
A Unique Verse
Zephaniah 3:8, according to Wilmington's Guide to Bible Knowledge, is the only Old Testament verse which includes every one of the 22 letters in the Hebrew alphabet.
Therefore wait ye upon me, saith the LORD, until the day that I rise up to the prey: for my determination is to gather the nations, that I may assemble the kingdoms, to pour upon them mine indignation, even all my fierce anger: for all the earth shall be devoured with the fire of my jealousy (Zephaniah 3:8).
Amazing Genealogy
Zephaniah is the only Old Testament prophet whose genealogy is known four generations previous. Most prophets only list the name of their father (e.g. "Jonah son of Amittai" found in Jonah 1:1).
The word of the LORD which came unto Zephaniah the son of Cushi, the son of Gedaliah, the son of Amariah, the son of Hizkiah (Hezekiah), in the days of Josiah the son of Amon, king of Judah. (Zephaniah 1:1).
Some Biblical commentaries argue that Zephaniah is of royal blood because the Hezekiah he references in his first verse was the same one who ruled Judah from 715 to 686. There are several reasons, however, to consider such a claim doubtful.

For starters, there is no Jewish or Christian tradition to support that Zephaniah was of royal blood, which there probably would have been if it had been true (Tyndale Bible Dictionary). Second, the name Hezekiah was not uncommon at the time the prophet wrote his book.
Additionally, Zephaniah himself does not identify him as king and Scripture does not record Hezekiah having a son named Amariah. The last point is that the prophet's father, named Cushi, could mean someone who was a Cushite or Ethiopian (Holman Bible Dictionary).
Dating Zephaniah
Zephaniah 1:1 reveals the prophet gave his message during the reign of Judah's King Josiah. Biblical history tells us the king, when he was only eight years old (2Kings 22:1), took the throne in 640 and ruled until 609 B.C. Are there clues within the Bible to help further narrow down when Zephaniah's book was likely written?
In chapter 2 the prophet mentions the fall of Nineveh as a future event. Since the city fell to the Babylonians and others in 612 B.C., Zephaniah must have been written before this year.
And he will stretch out his hand against the north, and destroy Assyria; and will make Nineveh a desolation, and dry like a wilderness (Zephaniah 2:13).
If we look a little more when can further narrow down the timeframe of this book.
[Important People in Old Testament]
Josiah, in the eighteenth year of his reign (2Kings 22:3, 2Chronicles 34:8) or 622 B.C., began a series of massive religious reforms. He had started to remove idolatry in the land in 628 B.C. (2Chronicles 34:3 - 7) but the reforms of 622 were far more sweeping.
Josiah's reforms were initiated by the discovery of the Book of the Law which caused the king to take uniquely bold actions. Not only was the temple cleared of anything that was pagan, the idolatrous priests in the land were killed! Idols were also destroyed along with the places used to worship them (2Kings 23).
Josiah's actions fulfilled a roughly 300 year old prophecy given to Israel's King Jeroboam (see 1Kings 13:1 - 2, 2Kings 23:15 - 17)!
Josiah's willingness to remove idolatrous practices in Judah, condemned in Zephaniah 1:4 - 5, led to God extending mercy to him and the nation (2Kings 22:18 - 20). With all the information above, we can conservatively place the writing of Zephaniah from between 640 and 622 B.C.
Day of the Lord
Zephaniah uses the term "Day of the Lord" or slight variation thereof seven times (Zephaniah 1:7, 8, 14, 18, 2:2 - 3). This is more than any other Old Testament prophet! The prophetic book of Joel uses it five times (Joel 1:15, 2:1, 11, 31, 3:14) while Isaiah uses it four times (Isaiah 2:12, 13:6, 9, 34:8).
The great day of the LORD is near, it is near, and hasteth greatly, even the voice of the day of the LORD: the mighty man shall cry there bitterly (Zephaniah 1:14).
[When is the Day of the Lord?]
New Testament References
Zephaniah is referenced or alluded to in six New Testament locations. Verse 14 of Zephaniah 1 is referenced in Revelation 6:17 while verse 15 is referenced in Mark 13:24 and verse 18 is alluded to in Hebrews 10:27. Zephaniah 2:15 is referred to in Revelation 18:7. Finally, verse 10 of chapter 3 is found in Acts 8:27 while verse 13 is referenced in Revelation 13:5.
More Than One
The name Zephaniah is recorded 10 times in 10 King James Bible verses. Other than the Minor Prophet, a priest of the same name during King Zedekiah's reign urged the king to resist Babylon (Jeremiah 21:1, 29:25).
God Will Sing!
The prophet Zephaniah, in describing the time when Jesus will rule the earth during the Millennium, makes an incredibly unusual statement.
The LORD thy God in the midst of thee is mighty; he will save, he will rejoice over thee with joy; he will rest in his love, HE WILL JOY OVER THEE WITH SINGING (Zephaniah 3:17).
God says he will rejoice over those whom, in his perfect love, he forgives and redeems. His delight over being with his people and blessing them will, in fact, be so great that he will SING with utter joy!