Apostasy in Islam ( or ) is commonly defined as the abandonment of all or part of Islam by a current or former Muslim, in thought, word, or through deed. It includes not only explicit apostasy, renunciations of the Islamic faith by converting to another religion or abandoning religion altogether, but also blasphemy or heresy by those who consider themselves Muslims, through any action or utterance which implies unbelief, including those who deny a "fundamental tenet or creed" of Islam. An apostate from Islam is known as a murtadd ().Frank Griffel, "Apostasy", in (Editor: Gerhard Bowering et al.) The Princeton Encyclopedia of Islamic Political Thought, , pp. 40–41Diane Morgan (2009), Essential Islam: A Comprehensive Guide to Belief and Practice, , pp. 182–183

While Islamic jurisprudence traditionally calls for the death penalty for those who refuse to repent of apostasy from Islam, what statements or acts qualify as apostasy, and whether or how they should be punished, are disputed among Muslim scholars, with liberal Islamic movements rejecting physical punishment for apostasy altogether. The penalty of killing of apostates is in conflict with international human rights norms which provide for the freedom of religions, as demonstrated in human rights instruments such as the Universal Declaration of Human Rights, the International Covenant on Civil and Political Rights, and the International Covenant on Economic, Social, and Cultural Rights.

Until the late 19th century, the majority of Sunni and Shia jurists held the view that for adult men, apostasy from Islam was a crime as well as a sin, punishable by the death penalty, but also allowed for a number of options for leniency (such as a waiting period to allow time for repentance or enforcement only in cases involving politics),Asma Afsaruddin (2013), Striving in the Path of God: Jihad and Martyrdom in Islamic Thought, p. 242. Oxford University Press. . depending on the era, the legal standards, and the particular school of law. In the late 19th century, the use of legal criminal penalties for apostasy fell into disuse, although civil penalties were still applied.

As of 2021, there were ten Muslim-majority countries where apostasy from Islam was punishable by death, but legal executions are rare. Most punishment is extrajudicial/vigilante in nature,Marshall, Paul; Shea, Nina. 2011. Silenced. How Apostasy & Blasphemy Codes are Choking Freedom Worldwide. Oxford: Oxford University Press. p. 61 and most executions are perpetrated by jihadist and takfiri insurgents (al-Qaeda, the Islamic State, the GIA, and the Taliban). Another thirteen countries have penal or civil penalties for apostatessuch as imprisonment, the annulment of their marriages, the loss of their rights of inheritance and the loss of custody of their children. In the contemporary Muslim world, public support for capital punishment varies from 78% in Afghanistan to less than 1% in Kazakhstan; among Islamic jurists, the majority of them continue to regard apostasy as a crime which should be punishable by death. Those who disagree argue that its punishment should be less than death and should occur in the afterlife,Forte, D. F. (1994), Apostasy and Blasphemy in Pakistan, Conn. Journal of Int'l Law, Vol. 10, pp. 27–41 as human punishment is considered to be inconsistent with Quranic injunctions against compulsion in belief, or that it should be applied only in cases of public disobedience and disorder (fitna). Despite potentially grave and life-threatening consequences, some Muslims in these areas continue to leave the Islamic religion, either becoming irreligious (atheism, agnosticism, etc.) or converting to other religions, mostly to Christianity.

Etymology and terminology Apostasy is called irtidād or ridda (which means "relapse" or "regress") in Islamic literature. An apostate is called murtadd, which means "one who turns back" from Islam. The Oxford Islamic Studies Online defines murtadd as "not just any kāfir (non-believer)" but "a particularly heinous type". Ridda can also refer to "secession" in a political context. A person born to a Muslim father who later rejects Islam is called a murtadd fitri, and a person who converted to Islam and later rejects the religion is called a murtadd milli.Mousavian, S. A. A. (2005), "A Discussion on the Apostate's Repentance in Shi'a Jurisprudence", Modarres Human Sciences, 8, Tome 37, pp. 187–210, Mofid University (Iran), quote: "Shi'a jurisprudence makes a distinction between an apostate who is born to Muslim parents (murtad-i fitri) and an apostate who is born to non-Muslim parents (murtad-i milli)." (section 1.3)Advanced Islamic English dictionary Расширенный исламский словарь английского языка (2012), see entry for Fitri MurtadAdvanced Islamic English dictionary Расширенный исламский словарь английского языка (2012), see entry for Milli Murtad Takfīr () is the act of one Muslim excommunicating another, declaring them a kāfir, an apostate. The act which precipitates takfīr is termed mukaffir.

Scriptural references

Quran The Quran references apostasy (2:108, 66; 10:73; 3:90; 4:89, 137; 5:54; 9:11–12, 66; 16:06; 88:22–24) in the context of attitudes associated with impending punishment, divine anger, and the rejection of repentance for individuals who commit this act. Traditionally, these verses are thought to "appear to justify coercion and severe punishment" for apostates (according to Dale F. Eickelman), including the traditional capital punishment. Other scholars, by contrast, have pointed to a lack of any Quranic passage requiring the implementation of force to return apostates to Islam, nor any specific corporal punishment to apply to apostates in this worldAsma Afsaruddin (2013), Striving in the Path of God: Jihad and Martyrdom in Islamic Thought, p. 242. Oxford University Press. . Quote: "He [Al-Banna] notes that the Qur'ān itself does not mandate any this-worldly punishment for religious apostasy but defers punishment until the next (cf. Qur'ān 2:217)." – let alone commands to kill apostates – either explicitly or implicitly.Taha Jabir Alalwani (2003), La 'ikraha fi al-din: 'ichkaliyat al-riddah wa al-murtaddin min sadr al-Islam hatta al-yawm, pp. 93–94. . Some verses have been cited as emphasizing mercy and a lack of compulsion with respect to religious belief (2:256; 4:137; 10:99; 11:28; 18:29; 88:21–22).

Hadith

The classical shariah punishment for apostasy comes from Sahih ("authentic") Hadith rather than the Quran.Sherazad Hamit (2006), "Apostasy and the Notion of Religious Freedom in Islam", Macalester Islam Journal, Volume 1, Spring 2006 Issue 2, pp. 32–38David Forte (1994), "Apostasy and Blasphemy in Pakistan", Conn. Journal Int'l Law, Vol. 10, pp. 43–45, 27–47 Writing in the Encyclopedia of Islam, Heffening holds that contrary to the Quran, "in traditions [i.e. hadith], there is little echo of these punishments in the next world... and instead, we have in many traditions a new element, the death penalty."

Other hadith give differing statements about the fate of apostates;Frank Griffel (2007), '"Apostasy", in Encyclopedia of Islam, 3rd ed., Leiden: Brill, Eds: Gudrun Kramer et al, Vol. 1, p. 132 that they were spared execution by repenting, by dying of natural causes or by leaving their community (the last case sometimes cited as an example of open apostasy that was left unpunished).Dr. M. E. Subhani (2005), Apostasy in Islam, pp. 23–24. New Delhi, India: Global Media Publications. Quote: "This was an open case of apostasy. But the Prophet neither punished the Bedouin nor asked anyone to do it. He allowed him to leave Madina. Nobody harmed him."

The Muwatta of Imam Malik offers a case were Rashidun (rightly guide) Caliph Umar admonishes a Muslim leader for not giving an apostate the opportunity to repent before being executed:

The argument has been made (by the Fiqh Council of North America, among others) that the hadiths above – traditionally cited as proof that apostates from Islam should be punished by death – have been misunderstood. In fact (the council argues), the victims were executed for changing their allegiances to the armies fighting the Muslims (i.e. for treason), not for their personal beliefs. As evidence, they point to two hadith, each from a different "authentic" (sahih) Sunni hadith collection where Muhammad calls for the death of apostates or traitors. The wording of the hadith are almost identical, but in one, the hadith ends with the phrase "one who reverts from Islam and leaves the Muslims", and in the other it ends with "one who goes forth to fight Allah and His Apostle" (in other words, the council argues the hadith were likely reports of the same incident but had different wording because "reverting from Islam" was another way of saying "fighting Allah and His Apostle"):

Definition of apostasy in Islam Scholars of Islam differ as to what constitutes apostasy in that religion and under what circumstances an apostate is subject to the death penalty.

Conditions of apostasy in classical Islam

Al-Shafi'i listed three necessary conditions to pass capital punishment on a Muslim for apostasy in his Kitab al-Umm. (In the words of Frank Griffel) these are: "first, the apostate had to once have had faith (which, according to Al-Shafi'i's definition, means publicly professing all tenets of Islam); secondly, there had to follow unbelief (meaning the public declaration of a breaking-away from Islam), (having done these two the Muslim is now an unbeliever but not yet an apostate and thus not eligible for punishment); "third, there had to be the omission or failure to repent after the apostate was asked to do so."Griffel, Frank, Toleration and exclusion: al-Shāfi'ī and al-Ghazālī on the treatment of apostates, Cambridge University Press, 2001, p. 348 Three centuries later, Al-Ghazali wrote that one group, known as "secret apostates" or "permanent unbelievers" (aka zandaqa), should not be given a chance to repent, eliminating Al-Shafi'i's third condition for them although his view was not accepted by his Shafi'i madhhab.Al-Ghazali, Fayasl al-tafriqa bayn al-Islam wa-l-zandaqa, p. 222

Characteristics Describing what qualifies as apostasy or unbelief in Islam, religion scholar Christine Schirrmacher writes: [...] there is widespread consensus that apostasy undoubtedly exists where the truth of the Koran is denied, where blasphemy is committed against God, Islam, or Muhammad, and where breaking away from the Islamic faith in word or deed occurs. The lasting, willful non-observance of the five pillars of Islam, in particular the duty to pray, clearly count as apostasy for most [Muslim] theologians. Additional distinguishing features are a change of religion, confessing atheism, nullifying the Sharia as well as judging what is allowed to be forbidden and judging what is forbidden to be allowed. Fighting against Muslims and Islam (Arabic: muḥāraba) also counts as unbelief or apostasy;

Kamran Hashemi classifies apostasy or unbelief in Islam into three different "phenomena": Converting from Islam to another religion (or abandoning religion altogether), also described as "explicit" apostasy. (Hashemi gives the example of Abdul Rahman, an Afghan who was arrested in February 2006 and threatened with the death penalty in a lower court in Kabul for converting to Christianity). Blaspheming (sabb) (by a Muslim) against God, Islam, its laws or its prophet, which can be defined, in practice, as any objection to the authenticity of Islam, its laws or its prophet.