This page is part of “Problems with Religions and Spiritual Traditions”.

Within a religious tradition, some adherents slide from ordinary devotion into fundamentalism and zealotry: an unwavering conviction that their interpretation is the sole truth, a very strict and rigid adherence to it, and a willingness to act on it at any cost. Zealots prioritize doctrinal purity over compassion, becoming willing to harm others, or even sacrifice their own lives, in the name of the cause — turning people into perpetrators of extremism and violence.

While the pages on Coercion and Religious violence describe what is done to others, this page is about the mindset behind it: what happens inside a believer, and inside a community, when devotion hardens into zealotry. Its victims are often not only outsiders, but the zealots’ own people, and the zealots themselves.

What these words mean

The origin of “fundamentalism”

Between 1910 and 1915, American Protestants published The Fundamentals, a series of 90 essays defending what they saw as the fundamentals of Christianity, including the literal truth of the Bible, against modern theology, biblical criticism, and the theory of evolution. In 1920, a Baptist minister coined the word “fundamentalist” for those ready to do “battle royal” for the fundamentals. Today the word describes a pattern found in many religions: a literal reading of scripture, total certainty, a longing to return to a “pure” original faith, rejection of modernity, and a sharp boundary between “us” and “them”.

The origin of “zealotry”

The Zealots were a Jewish movement in first-century Judea, founded on “zeal” — total commitment to God’s law — who sought to free the land of Israel from Roman rule by force. They played a leading role in the Great Revolt against Rome (66–73 CE), which ended with the destruction of Jerusalem and the Second Temple in 70 CE. A radical faction, the Sicarii (“dagger-men”), assassinated not only Romans but also fellow Jews whom they considered collaborators.

Turning on their own

The zealot’s most typical target is often not the outsider, but the “traitor” within: the moderate, or the leader who compromises.

Example: The zealots burn Jerusalem’s food

During the Roman siege of Jerusalem, according to the Talmud (Gittin 56a), “The Sages said to them: Let us go out and make peace with the Romans. But the zealots did not allow them to do this.” To force the people to fight, “the zealots arose and burned down these storehouses of wheat and barley, and there was a general famine.” The famine helped doom the city, which the Romans destroyed along with the Temple.

Example: Three assassinated peacemakers
  • In 1948, Mahatma Gandhi was shot by Nathuram Godse, a Hindu nationalist, who believed Gandhi had been too accommodating to Muslims and to Pakistan.
  • In 1981, Egypt’s President Anwar Sadat was shot during a military parade by army officers belonging to the group Egyptian Islamic Jihad, who opposed his peace treaty with Israel.
  • In 1995, Israel’s Prime Minister Yitzhak Rabin was shot by Yigal Amir, a Jewish religious nationalist opposed to the Oslo Accords. Amir justified the murder with din rodef, the Jewish law allowing one to kill a “pursuer” who threatens Jewish lives: “I acted according to din rodef.” Before the murder, pamphlets debating whether din rodef applied to Rabin had been distributed in synagogues.

In each case, the killer shared the religion of the leader he killed.

Purity over compassion

Zealots may keep the rules even when real people pay the price — often their own children.

Example: Faith-healing churches

The Followers of Christ, a small church in Oregon and Idaho, rejects modern medicine and relies on faith healing and prayer alone. An investigation by the newspaper The Oregonian found that at least 21 of the 78 children buried in the church’s cemetery had died of preventable causes, such as treatable infections. In 2008, 16-year-old Neil Beagley died of a treatable urinary blockage, and his parents were convicted of criminally negligent homicide. In 2011, Oregon removed religious belief as a legal defense in such cases.

Example: Jehovah’s Witnesses and blood transfusions

Since 1945, Jehovah’s Witnesses have forbidden blood transfusions, based on biblical verses commanding to “abstain from blood” (Acts 15:29) — even when a transfusion is needed to save a life. A member who accepts one without repenting is considered to have left the religion, and is shunned. The organization has acknowledged that some members died after refusing blood, and in countries such as Canada and the UK, courts and doctors can overrule parents who refuse a life-saving transfusion for their child.

Giving up one’s own life

The ultimate expression of zealotry is the willingness to die for the cause — and, too often, to take as many others as possible along.

Suicide bombings

Suicide bombing is the clearest case of zealotry: the bomber sacrifices his own life, believing that he is guaranteed a place in paradise, in order to murder as many people as possible, chosen only for belonging to the “enemy” — often simply for being “infidels”. Islamist groups call these attacks “martyrdom operations”, and the bomber is honored as a shahid (“martyr”), drawing on Quranic verses such as “Never think of those martyred in the cause of Allah as dead. In fact, they are alive with their Lord” (3:169).

Example: Suicide bombings in Israel

Between 1994 and 2005, Palestinian suicide bombings killed 735 Israelis and wounded 4,554, most of them during the Second Intifada (2000–2005). Most were carried out by the Islamist movement Hamas, and others by Palestinian Islamic Jihad and Fatah factions. The bombers deliberately chose places full of civilians — buses, restaurants, nightclubs, and markets — and packed their explosives with ball bearings and nails to maximize casualties. Some of the deadliest attacks:

  • The Dolphinarium, Tel Aviv, June 1, 2001: A Hamas bomber blew himself up among young people waiting to enter a beachfront disco, killing 21, most of them teenage girls from families that had recently immigrated from the former Soviet Union (Wikipedia).
  • The Passover massacre, Netanya, March 27, 2002: A Hamas bomber disguised as a woman blew himself up in the dining room of the Park Hotel, among some 250 people celebrating the Passover seder, most of them elderly. 30 were killed — the deadliest attack on Israeli civilians during the Second Intifada (Wikipedia).
  • Bus No. 2, Jerusalem, August 19, 2003: A Hamas bomber disguised as an ultra-Orthodox Jew blew himself up on a crowded bus carrying families home from prayers at the Western Wall. 23 people were killed, many of them children (Wikipedia).

The bombers were celebrated as heroes: their communities held mass funerals, and named streets and public spaces after them. Iraq’s dictator Saddam Hussein paid $25,000 to the family of each suicide bomber.

Example: September 11, 2001

On September 11, 2001, 19 al-Qaeda terrorists hijacked four passenger airplanes in the US. They flew two of them into the Twin Towers of the World Trade Center in New York, and one into the Pentagon near Washington; the fourth crashed in a field in Pennsylvania after the passengers fought back. 2,977 people were killed — the deadliest terrorist attack in history. In a 1998 fatwa, al-Qaeda’s leader Osama bin Laden had declared: “We do not differentiate between those dressed in military uniforms, and civilians; they are all targets of this fatwa.”

A handwritten document found in the luggage of the ringleader, Mohamed Atta — The Last Night — combined practical instructions with religious exhortation, promising the hijackers: “the gardens of paradise are waiting for you in all their beauty, and the women of paradise are waiting, calling out ‘Come hither, friend of God’.”

Mass suicide in cults

Example: Jonestown

On November 18, 1978, at the remote commune of the Peoples Temple in Guyana, its leader Jim Jones ordered his followers to drink cyanide-laced Flavor Aid, calling it “revolutionary suicide”. 918 people died, including about 300 children (Wikipedia). Armed guards prevented escape, and many were forcibly injected with poison, so it was a mass murder-suicide rather than a mass suicide. Similarly, in 1997, 39 members of the “Heaven’s Gate” group in California took their own lives, believing their souls would be taken aboard a spaceship.

How devotion becomes zealotry

The slide into zealotry often combines several ingredients: absolute certainty; isolation from outside views; a sense of grievance, or of threat to the faith; and a “purity spiral”, in which each member proves their loyalty by being stricter than the last. The anthropologist Scott Atran, who studied terrorists and the people who fight them, describes zealots as “devoted actors” committed to “sacred values”: values that cannot be traded off against anything else, including life itself. Such people cannot be bought off — offering them money to compromise only makes them angrier.

Some distinctions

At the same time, fairness requires some distinctions.

Strictness is not zealotry

Many strictly observant, conservative believers are peaceful, humble, and kind. The Amish, for example, are both very strict and committed pacifists. The problem is not strictness, but certainty combined with a willingness to harm.

Most believers reject it

The vast majority of believers in every religion reject violent zealotry. Mainstream Islam forbids suicide (“do not kill yourselves”, Quran 4:29) and the killing of innocents, and in 2010 the Pakistani scholar Muhammad Tahir-ul-Qadri issued a 600-page fatwa condemning terrorism and suicide bombings as un-Islamic, without “ifs and buts”.

Fundamentalism is modern

Historians such as Karen Armstrong (The Battle for God, 2000) describe fundamentalism as a modern reaction to modernity, rather than a return to how religion used to be.

Secular zealotry exists too

The same pattern appears in secular ideologies. The Tamil Tigers in Sri Lanka, a secular nationalist movement, had a dedicated suicide-bombing unit, the “Black Tigers”, which in 1991 assassinated India’s former Prime Minister Rajiv Gandhi. Revolutionary political movements have shown the same certainty, purity spirals, and willingness to kill and die for the cause. The problem is the zealot’s mindset, not religion as such.