A religious war or a war of religion, sometimes also known as a holy war (Latin: bellum sacrum), is a war which is primarily caused or justified by differences in religion. In the modern period, there are frequent debates over the extent to which religious, economic, ethnic or other aspects of a conflict are predominant in a given war. The degree to which a war may be considered religious depends on many underlying questions, such as the definition of religion, the definition of 'religious war' (taking religious traditions on violence such as 'holy war' into account), and the applicability of religion to war as opposed to other possible factors. Answers to these questions heavily influence conclusions on how prevalent religious wars have been as opposed to other types of wars.
According to scholars such as Jeffrey Burton Russell, conflicts may not be rooted strictly in religion and instead may be a cover for the underlying secular power, ethnic, social, political, and economic reasons for conflict. Other scholars have argued that what is termed "religious wars" is a largely "Western dichotomy" and a modern invention from the past few centuries, arguing that all wars that are classed as "religious" have secular (economic or political) ramifications. In several conflicts including the Israeli–Palestinian conflict, the Syrian civil war, and the wars in Afghanistan and Iraq, religious elements are overtly present, but variously described as fundamentalism or religious extremism—depending upon the observer's sympathies. However, studies on these cases often conclude that ethnic animosities drive much of the conflicts.
According to the Encyclopedia of Wars, out of all 1,763 known/recorded historical conflicts, 121, or 6.87%, had religion as their primary cause. Matthew White's The Great Big Book of Horrible Things gives religion as the primary cause of 11 of the world's 100 deadliest atrocities.
[Christianity] Pope Urban II called for the first crusade in 1095. After that, until the Reformation, pope after pope called upon Christian armies to attack Muslim lands. Subsequent popes knew full well that the first crusade had resulted, as the chroniclers said, in the blood of Muslims flowing over the temple mount. Yet for centuries these extremely violent conflicts were initiated by the popes, and indeed imposed as a moral condition on monarchs who faced excommunication if they refused to go.
[Islam] The notion of religious justification for war persists, and threats of Jihad, or holy war, were still heard in the second half of the 20th century. While the influence of the mullah, mufti and other Moslem jurists, theologians and intellectuals is to internalize the Jihad and thus make it a personal struggle to attain moral improvement by self-conquest, the lack of restraint of some popular leaders, militarists, fundamentalists and oil supported politicians in invoking the traditional fourth way appeals to the emotions of the uneducated and threatens peaceful solutions to problems of Islamic and world concern.
Where Shiite Moslems fight Sunni Moslems, as in Lebanon, or in the case of Iran versus Iraq, each faction may also invoke the Jihad tradition, not unlike the clerically-blessed conflicts of Christian Europe. In 1990, Saddam Hussein, as president of Iraq declared a jihad against the forces arrayed against him.
In May 1997 during an interview with CNN, Osama Bin Laden reaffirmed his call for a holy war against Americans. "We have focused our declaration of jihad on the U.S. soldiers inside Arabia. The U.S. government has committed acts that are extremely unjust, hideous and criminal through its support of the Israeli occupation of Palestine." In February 1997 Bin Laden threatened holy war against the U.S. in an interview on the British documentary program, Dispatches. "This war will not only be between the people of the two sacred mosques and the Americans, but it will be between the Islamic world and the Americans and their allies because this war is a new crusade led by America against the Islamic nations."
2. Muslims believe that the solution to the problem of Palestine is a holy war against Israel and all the powers that support the occupation of Palestine.
2. The use of the sword is the Islamic fourth way of performing the religious duty of defending and propagating the faith. The first three means are by the heart, by the tongue and by the hand.