Jezebel, whose name means "Baal exalts," was born a Phoenician princess through her father Ethbaal (which means "with Baal") the King of Sidon (1Kings 16:31). As princess, she also served as a high priestess of Baal, the primary god worshipped by her people. Israel's King Ahab, desiring to solidify an alliance with the Phoenicians, married her in spite of the Lord's command not to do so (Deuteronomy 7:1 - 4).
Jezebel was a zealous supporter and worshipper of not only Baal but also Ashtaroth (Astarte), Baal's female counterpart. Her goal, after marrying Ahab, was the replace Israel's worship of the true God with pagan deities. The queen wasted no time as, soon after her marriage, she convinced her husband to build a temple for Baal in the capital city of Samaria as well as erecting idolatrous poles to Astarte (1Kings 16:32 - 33).
The queen possessed an unusually aggressive personality that was the driving force behind Israel's indulgence in evil during this period in history. She dominated Ahab and led him to practice far more wickedness than he would otherwise (1Kings 21:25). The Bible records several examples of her acting not like a queen but like a king who possessed absolute authority accountable to no one!
A pattern of evil
It was Jezebel, not Ahab, that initiated a slaughter of God's servants and prophets, ultimately replacing them with hundreds of priests of Baal and Asherah (1Kings 18:4, 19).
It was Jezebel who actively sought to kill Elijah after his famous contest on Mount Carmel which resulted in the death of Baal's prophets (1Kings 18, 19:1 - 4). Her reputation and determination to kill the prophet so scared Elijah that it motivated him to flee to the wilderness.
King Ahab's response for failing to buy Naboth's land, located near his palace, was to sulk like a little child and refuse to eat! Jezebel, when she witnessed this childish behavior, chastised the king for not exercising absolute authority over the people.
The queen then immediately executed a plan whereby she forged letters in Ahab's name and sealed them with his royal seal. She then sent the letters to leaders living near Naboth that commanded them to falsely accuse him of blasphemy and stone him to death. The queen, after the leaders successfully carry out her order, informs Ahab he can take possession of the land he greatly desired (1Kings 21:1 - 16).
God's vengeance
The evil of Ahab and Jezebel ultimately brings God's wrath upon them. The king, as was prophesied, is killed in battle in 853 B.C. (1Kings 21:19). The queen is allowed to live beyond her husband's death until 841 when, defiant and self-righteous to the end, she loses her life when she is tossed out of her window by some servants and dies. Her dead body is then torn into pieces and eaten by animals as was foretold (2Kings 9:35 - 37).
New Testament reference
Thyatira is one of Revelation's seven churches given a spiritual assessment by Jesus. His primary criticism of the church is that they allowed a woman, symbolically named Jezebel, to promote sexual immorality and other pagan practices common with the worship of false gods.
But I have a few things against you, because you allow the woman Jezebel, who calls herself a prophetess, to teach and to seduce My servants into committing fornication and eating things sacrificed to idols (Revelation 2:20, HBFV).
The spirit of Jezebel, as seen in Thyatira, manifests itself when someone wrongfully appropriates a leadership role in the church for the express purpose of deceiving others. The goal of such people is to lead believers away from worshipping the true God and entice them to serve that which is a lie.