Jihad, from an Arabic root meaning to strive or to struggle, names in classical Islamic thought a range of effort undertaken for the sake of God, of which armed struggle is only one form and, in the tradition's own internal ranking, generally considered the lesser one. A hadith widely cited across classical sources, though its precise chain of transmission has been questioned by some hadith scholars, has the Prophet Muhammad returning from a military campaign and declaring that the community had returned from the lesser jihad, al-jihad al-asghar, to the greater jihad, al-jihad al-akbar, the struggle against one's own soul and its base inclinations.
Classical Islamic scholarship built an extensive juristic literature specifically around jihad in its martial sense, treating it as a distinct category of religious law, fiqh al-jihad, with its own conditions, forms and rules of conduct, rather than as a single simple concept, distinguishing at minimum defensive jihad, obligatory on the whole community when Muslim territory is attacked, from more restricted forms requiring authorization from a legitimate ruler. Classical legal manuals accordingly devote separate chapters to each category, treating fiqh al-jihad as a specialized field of religious law with its own recognized experts, comparable in status to other major divisions of Islamic jurisprudence.