Introduction The just war theory is a theory that describes the occurrence of war and tries to justify the occurrence with reference to various issues such as tradition, doctrine, and history. This theory was developed by the Greek society where they employed concepts such as good intentions, a just cause, and proportionality for the purpose of just judgment. This theory however was later developed by Christian theorists and the theory depicts that certain forms of war are just given certain conditions. According to classical Islam, jihad is a religious practice whereby is termed a holy war, according to Islam Jihad is the sixth pillar of their religion and it is one of its practices. The term literally means a struggle in the ways of God or oneself or even society. Therefore Jihad is a war justified by the Islam religion as a practice to struggle for justice. The just war theory Traditionally the just war theory decision on just war was determined through a moral core, the just war theory, therefore, tries to describe a war in different contest and they include when it would be right to achieve justice through armed forces, and what would be acceptable in using such forces and the justice of terminating the war. Therefore the just war theory focuses on the use of morality in decisions to go to war. A Just War According To the Just War Theory   * A just cause: war can be justified if the reason for the war is intended to recapture or intended to punish wrongdoing.   * Justice: war may be justified if it’s intended to achieve comparative justice   * Authority: war may be just according to the just war theory if it is perpetrated by legitimate authority   * Right intention : war may be justified if it is intended for the right intention example if the war is intended to punish wrong   * Last resort: war may be justified according to this theory if war is used as a last resort when all other means of achieving justice have failed   * Success: war may also be justified if it is intended for success when all other means of achieving are inappropriate JIHAD Jihad’s just warfare is a struggle in the way of God, further Islam divide their just warfare into two namely:   * Just war against oppression and injustice   * Just war against those who reject the truth even when the truth is told to them The directions of Jihad or holy war are given in the Quran, which is the Islam holy book used for religious teachings. Emperor constantine Constantine was a Roman emperor who commanded a large army in the emperor, during his reign he put an end to Christian persecution, before he transformed into Christianity he previously was involved in the persecution of Christians, and after transforming he put an end to the institutionalized persecution of Christians in the Roman Empire. According to the just war by the Christians, there was no need for war against the emperor because there was a just reason to terminate a war against him, the just reason for termination was that the emperor was willing to negotiate the terms and become a Christian. According to Jihad the making of the emperor a religious person would have been impossible, this is because the Muslim believes that a war is a struggle in the way of God, also a just war by the Muslim is that which is against oppression and injustice. It is also a contrast with the jihad that war is not meant to obtain wealth and riches and this can be seen as a contrast with the Christians whereby they accepted their previous persecutor to be one of them so that they would gain popularity and end the injustice. According to Jihad, the war against persecution should not end, the direction is that the war should continue until oppression comes to