The “dagger men” were members of a fanatical political Jewish faction existing in the first century C.E. that engaged in organized political killings. When the Jews rioted against Paul at Jerusalem during his last visit there, the military commander Claudius Lysias suspected the apostle of being the Egyptian who had previously stirred up sedition and had led the 4,000 “dagger men” into the wilderness.​—Ac 21:30-38; 23:26, 27.

The Greek expression translated “dagger men” literally means “men of the Sicarii.” The Greek word for “Sicarii” (si·kaʹri·oi) comes from the Latin sicarii, which, in turn, is derived from sica (dagger).

According to the Jewish historian Josephus, especially during the festivals, the “dagger men,” or Sicarii, with daggers concealed under their  garments, mingled among the crowds at Jerusalem and stabbed their enemies in broad daylight. Then, to avoid suspicion, they joined those expressing indignation about the killings. Josephus further indicates that the Sicarii took a leading part in the revolt against Rome. In 66 C.E., a band of Sicarii, under the command of Eleazar, son of Jairus, seized and massacred the Roman garrison at Masada. This band of fanatical patriots continued their defiance of Rome until 73 C.E., in which year the defenses of Masada were breached. The Romans, however, did not have to make an assault on the fortress itself. In order to avoid being captured, the Sicarii had carried out a systematic suicidal massacre of 960 men, women, and children. Only two women and five children, who had hidden in a cave, survived.