The lawless Simon Bar-Giora, who had kindled the war in Jerusalem, could not rest in Masada, where the Sicarii had received him, for he was ambitious and eager for action. Thus he left the fortress, and collecting a number of slaves, to whom he held out promises of freedom and plunder, appeared before Jerusalem, ready to play an important part in the war. But the Zealots were afraid of him, and wished to make him powerless. They did not dare meet him in open battle, for he had already been their conqueror; so they waited in ambush, and made his wife and some of his soldiery prisoners, hoping to crush him by this cowardly action. But Bar-Giora was a stern-hearted warrior, and, in retaliation, threw himself upon the defenseless Judæans who ventured outside the walls to procure the necessaries of life. The Judæans, alarmed at this revenge, sent back his wife, while Bar-Giora was more determined than ever to make himself master of the capital. Day and night he waited and watched for some means of ingress, and at last he obtained what he wished through the party of the aristocrats.
In spite of the loss of their most prominent men, this party had not really ceased to exist, but was secretly working to destroy the power of the Zealots. At their head stood the high-priest Matthias, the son of Boëthus, and others belonging to the great priestly families. They knew how to enlist upon their side many of the populace who were unable to leave the city, and who were afraid of the consequences of the civil war. In league with the Idumæans, they suddenly made a well-directed attack upon the Zealots, over whom they gained a signal, but only a momentary advantage, for, recovering themselves from this defeat, the Zealots assembled upon the Mount of the Temple, and prepared to show a bold front to their opponents. The latter, much discomfited, appealed to Bar-Giora for assistance, and thus a fatal division was brought within the very walls of Jerusalem.
With the entry of this commander, civil war began in its most terrible form. Bar-Giora commanded his followers to surround the Mount of the Temple, where the Zealots lay entrenched. From the galleries and from the roofs the besieged were able not only to defend themselves, but also to repulse their assailants. In spite of his impatience, Bar-Giora was obliged to withdraw and to take up a safer position in the town.