Modern extremist groups have revived the use of certain concepts of Islamic dogma and wilfully misinterpreted them as a means of achieving their own ends. Dae‘sh (Islamic State of Iraq and Syria) is the most striking example. They have made declarations of takfir (excommunication) regarding Muslim rulers, maintaining that only Dae‘sh land is a dar al-Islam (abode of Islam) and that other lands are dar al-kufr or harb (abodes of unbelief or war), just as the Khawarij sect believed in the 7th century ce. They do not employ the concept of hijra (migration) in its traditional, defensive sense, but rather as a means of strengthening their own power by recruiting from around the world and launching military jihads, all in order to ‘reclaim’ the dar al-kufr and establish an Islamic state. This article examines the evolution of these terms throughout Islamic history, their misinterpretation by extremist groups, and their modern legal status.