Almost always implicitly or explicitly used with the phrase fi sabil Allah or “in the path of Allah,” the word jihad means “to strive in the path of Allah.” Citing the Encyclopedia of Islam, David Cook explains that “jihad consists of military action with the object of the expansion of Islam”; the explanation common among American Muslims that “‘jihad is entirely peaceable and represents the exertion of spiritual warfare,’” he adds, “is not the word's primary meaning.” Michael Bonner notes that “several other Arabic words are closely related to jihad in meaning and usage. These include ribat, which denotes pious activity, often related to warfare.… Ghazw, ghazwa, and ghaza have to do with raiding.” Then there is qital, which means “fighting” or “killing,” as well as harb, the word for “war”; “qital in the path of God,” notes Reuven Firestone, “is virtually synonymous with jihad.” A Jihadist, by sacred Islamic definition, must fight and kill in order to be righteous.

Although the Quran has never been the only source of inspiration for jihad, it has always been the most important source. Majid Khadduri elaborates: “The term jihad is derived from the verb jahada (abstract noun, juhd) which means ‘exerted’; its juridical-theological meaning is exertion of one's power in Allah's path, that is, the spread of the belief in Allah and in making His word supreme over this world.”