‘At its core, Islam is a religious mission to all humanity. Muslims are religiously obliged to disseminate the Islamic faith throughout the world. "We have sent you forth to all mankind" (Q. 34:28). If non-Muslims submit to conversion or subjugation, this call (da’wa) can be pursued peacefully. If they do not, Muslims are obliged to wage war against them. In Islam, peace requires that non-Muslims submit to the call of Islam, either by converting or by accepting the status of a religious minority (dhimmi) and paying the imposed poll tax, jizya. World peace, the final stage of the da’wa, is reached only with the conversion or submission of all mankind to Islam…Muslims believe that expansion through war is not aggression but a fulfillment of the Qur’anic command to spread Islam as a way of peace. The resort to force to disseminate Islam is not war (harb), a word that is used only to describe the use of force by non-Muslims. Islamic wars are not hurab (the plural of harb) but rather futuhat, acts of “opening” the world to Islam and expressing Islamic jihad. Relations between dar al-Islam, the home of peace, and dar al-harb, the world of unbelievers, nevertheless take place in a state of war, according to the Qur’an and to the authoritative commentaries of Islamic jurists. Unbelievers who stand in the way, creating obstacles for the da’wa, are blamed for this state of war, for the da’wa can be pursued peacefully if others submit to it.
In other words, those who resist Islam cause wars and are responsible for them.'