JIHAD

Jihad means "to strive or struggle" (in the way of God) and is considered the "sixth pillar of Islam" by a minority of Sunni Muslim authorities. Jihad, in its broadest sense, is classically defined as "exerting one's utmost power, efforts, endeavors, or ability in contending with an object of disapprobation." Depending on the object being a visible enemy, the devil, and aspects of one's own self, different categories of Jihad are defined. Jihad when used without any qualifier is understood in its military aspect. Jihad also refers to one's striving to attain religious and moral perfection. Some Muslim authorities, especially among the Shi'a and Sufis, distinguish between the "greater jihad", which pertains to spiritual self-perfection, and the "lesser jihad", defined as warfare.
Within Islamic jurisprudence, jihad is usually taken to mean military exertion against non-Muslim combatants in the defense or expansion of the Islamic state, the ultimate purpose of which is to universalize Islam. Jihad, the only form of warfare permissible in Islamic law, may be declared against apostates, rebels, highway robbers, violent groups, unIslamic leaders or states which refuse to submit to the authority of Islam. Most Muslims today interpret Jihad as only a defensive form of warfare: the external Jihad includes a struggle to make the Islamic societies conform to the Islamic norms of justice.
Under most circumstances and for most Muslims, jihad is a collective duty (fard kifaya): its performance by some individuals exempts the others. Only for those vested with authority, especially the sovereign (imam), does jihad become an individual duty. For the rest of the populace, this happens only in the case of a general mobilization. For most Shias, offensive jihad can only be declared by a divinely appointed leader of the Muslim community, and as such is suspended since Muhammad al-Mahdi's occultation in 868 AD