Harbi ( literally belonging to war) is a term of classical Islamic law, which refers to a non- Muslim, who does not live under the condition of the dhimma. Harbi is counterterm to dhimmi. Sometimes the terms appear in the combination "kafir harbi" resp. "kafir dhimmi".
According to the Middle East Media Research Institute Yusuf al-Qaradawi said:"It has been determined by Islamic law that the blood and property of people of Dar Al-Harb [the Domain of Disbelief where the battle for the domination of Islam should be waged] is not protected. Because they fight against and are hostile towards the Muslims, they annulled the protection of his blood and his property."1
According to the Middle East Media Research Institute the Egyptian Grand- Mufti, Dr. Sheikh Ali Gomaa, said on Jihad and killing harbis:Question: "Is it permitted to kill an Israeli traveling outside the borders of his land?" Sheikh Gum'a: "Yes, it is permitted to kill him, because he is a Harbi and the Harbi spreads corruption throughout the face of the earth."2
However, this was in the context of a question asking for an Arabic response to a perceived corresponding failure of Israelis to distinguish between civilians and militants in its attacks.
Islamic law recognizes a division between two distinct societies. One is the dar al-Islam, the “house of Islam” and peace. The other one is the dar al-harb, the “house of war,” or the “house of the sword.” Dar al-harb is the world of the infidel and the region of perpetual warfare. Barring any treaty, anyone who comes from the dar al-harb has the status under Islamic law of harbi. According to three different sources on Islamic law—Shaybani’s Siyar: The Islamic Law of Nations by Majid Khadduri, Al-Hidayah, and Ibn Rushd’s The Distinguished Jurist’s Primer—the word harbi means “enemy".
Drawing from the Siyar, Khadduri defines harbi as “a person belonging to the territory of war, equivalent to an alien in modern terminology, but may be regarded as an enemy as well since he was also in a state of war with the Muslims.” In War and Peace in the Law of Islam, Khadduri writes: It follows that the existence of a dar al-Harb is ultimately outlawed under the Islamic jural order; that the dar al-Islam is permanently under jihad obligation until the dar al-Harb is reduced to non-existence; and that any community accepting certain disabilities must submit to Islamic rule and reside in the dar al-Islam or be bound as clients to the Muslim community. The universality of Islam, in its all-embracing creed, is imposed on the believers as a continuous process of warfare, psychological and political if not strictly military.
Khadduri states this as a matter of doctrine—because the “dar al-harb is ultimately outlawed under the Islamic jural order; … the dar al-Islam is permanently under jihad obligation until the dar al-harb is reduced to non-existence.” Reliance of the Traveller confirms this: There is no indemnity obligatory for killing a non-Muslim at war with Muslims (harbi), someone who has left Islam, someone sentenced to death by stoning for adultery by virtue of having been convicted in court, or those it is obligatory to kill by military action such as a band of highwaymen. As stated by Shaybani, affirmed by Khadduri, and confirmed by the Reliance of the Traveller, the term harbi retains its legal status in Islamic law. Since published shariah holds that the dar al-Islam is in an ongoing state of war with the dar al-harb, the legal theory indicates that all non-Muslims not a part of the dar al-Islam (and not under treaty) are classified as harbi.