If zeal is defined as earnest enthusiasm, especially for a cause, why is a zealot considered a fanatic? Because the original Zealots were dedicated to protecting a piece of ground, even at the expense of their lives.
The Zealots, first-century fundamentalists, were a Jewish sect founded by Judas of Gamala, who fiercely fought for God’s law against the Romans, who opposed it. After the Romans razed Jerusalem — despite the fanatic defense of the Zealots in A.D. 70 — a thousand of them bravely held out on the great rock on the edge of the Judean desert. It was the site of Herod the Great’s palace, now known as Masada.
When the heroic stand by the Zealots appeared doomed, and only 960 Zealots remained to face the 6,000-man Tenth Roman Legion, their leader, Eleazar ben Ya’ir, persuaded them to draw lots to select ten men to kill the remaining defenders. Each of these ten finally slew nine fellows and then punched his sword through his own body. The Zealots preferred to die as free men than to live as slaves.