Jewish religious terrorism is religious terrorism committed by extremists within Judaism motivated by religious rather than ethnic or nationalistic beliefs.
Some researchers on ethnic terrorism distinguish between ethnic terrorism and religious terrorism, but admit that the distinction between these forms of terrorism is often blurred in practice. Daniel Bymen, in his study on "The Logic of ethnic terrorism", argues that Jews operate far more as an ethnic group than as a community motivated by and organized according to religious doctrine. As good examples of Jewish terrorism based on ethnic, not religious grounds, or Zionist political violence, the author cites Jewish underground groups Irgun and Lehi, which operated against British law during the British Mandate of Palestine before the Israeli declaration of independence in 1948.
According to Mark Burgess, the 1st century Jewish political and religious movement called Zealotry was one of the first examples of the use of terrorism by Jews. They sought to incite the people of Judaea Province to rebel against the Roman Empire and expel it from Israel by force of arms. The term Zealot, in Hebrew kanai, means one who is on behalf of God. The most extremist groups of Zealots were called Sicarii. Sicarii used violent stealth tactics against Romans. Under their cloaks they concealed sicae, or small daggers, from which they received their name. At popular assemblies, particularly during the pilgrimage to the Temple Mount, they stabbed their enemies (Romans or Roman sympathizers, Herodians), lamenting ostentatiously after the deed to blend into the crowd to escape detection. In one account, given in the Talmud, Sicarii destroyed the city's food supply so that the people would be forced to fight against the Roman siege instead of negotiating peace. Sicarii also raided Jewish habitations and killed fellow Jews whom they considered apostates and collaborators.