Religion has historically played a central role in motivating rulers to start and individuals to participate in war. However, the decline of religion in international politics following the Peace of Westphalia and the inception of the modern nation-state system, which built and highlighted a sense of national identity, undermined the contribution of religion to politics and consequently, conflict. The case of the Iran−Iraq War, however, shows a different pattern in which religion did play a crucial role in motivating individuals to participate in war. Although the evidence suggests that religious motivations by no means contributed to Saddam’s decision to launch the war, an overview of the Iranian leaders’ speeches and martyrs’ statements reveals that religion significantly motivated people to take part in the war. While Iraqi leaders tried to mobilize the population by highlighting the allegedly Persian-Arab historical antagonism and propagating an Iraqi-centered form of Arab nationalism, Iranian leaders exploited religious symbols and emotions to encourage war participation, garner public support, alleviate the suffering of the people, and build military morale. The Iranian leadership painted the war as a battle between believers and unbelievers, Muslims and infidels, and the true and the false. This strategy turned out to be an effective tool of mobilization during wartime.