Zealous defenders of the Law and of the national life of the Jewish people; name of a party opposing with relentless rigour any attempt to bring Judea under the dominion of idolatrous Rome, and especially of the aggressive and fanatical war party from the time of Herod until the fall of Jerusalem and Masada. The members of this party bore also the name Sicarii, from their custom of going about with daggers ("sicæ") hidden beneath their cloaks, with which they would stab anyone found committing a sacrilegious act or anything provoking anti-Jewish feeling.
The philosophy of the Zealot movement was simple: There was only one God, and Israel was to serve him alone; the Torah and other writings of the Bible were the only guide to righteous living; and serving the emperor in any way, whether in worship, slavery, or paying taxes, was apostasy against God.
Josephus, who knew the Zealots, described their passion for freedom as unconquerable because they would serve no one but God. Violent resistance was considered a God-ordained responsibility since they believed God was on their side, they knew that they would triumph in the end. This led to their reputation for incredible bravery and tolerance for suffering.
The Zealots lived by the strictest conformity to the Torah. In addition, they refused to acknowledge anyone as king, since "you shall have no other gods" (Ex. 20:3). These defenders of freedom influenced Galilee in particular. They were committed to the Scriptures' promise of a coming anointed one who would be a great military leader and king, like David of times past. They knew they would soon prevail over the detested Romans and their collaborators, the Herodions (Jews who supported the Herods) and the Sadducees.
Judah, the founder of the Zealot movement, was executed. His sons Jacob and Simeon were both crucified approximately AD 48. Another son, Menahem, seized the fortress Masada at the beginning of the Jewish revolt (AD 66) in the first true military action of that war. The Roman weapons found there equipped the Zealots who led the revolt. Menahem, probably thought to be the Messiah, commanded the rebel forces until he was murdered by another Zealot. A descendant of Judah, Eleazar Ben Jair, fled to Masada and assumed command of the forces there. John of Gischala, another Zealot, futilely defended Jerusalem and the Temple Mount against the Romans. The Romans threw the Zealots and their children off the city wall to their deaths, and destroyed the Temple and the city.
In AD 73, the Romans, under the command of Titus, laid siege to Masada. Eleazar, a descendant of Judah of Gamla, and his Zealots held out until there was no hope. They chose to kill their families and each other rather than serve anyone but God. With that mass suicide, the Zealot movement ended.