Like Christianity, Islam permits fighting in self-defense, in defense of religion, or on the part of those who have been expelled forcibly from their homes. It lays down strict rules of combat that include prohibitions against harming civilians and against destroying crops, trees and livestock. As Muslims see it, injustice would be triumphant in the world if good people were not prepared to risk their lives in a righteous cause.
One reads in the Qur'an: "Fight in the cause of God against those who fight you, but do not transgress limits. God does not love transgressors." (Qur'an 2:190)
"And fight them until persecution is no more, and religion is for God. But if they desist, then let there be no hostility except against wrongdoers." (Qur'an 2:193)
"If they seek peace, then you seek peace. And trust in God for He is the One that hears and knows all things." (Qur'an 8:61)
War is therefore the last resort, and is subject to the rigorous conditions laid down by the sacred law. The often misunderstood and overused term jihad literally means "struggle" and not "holy war" (a term not found anywhere in the Qur'an). Jihad, as an Islamic concept, can be on a personal level--inner struggle against evil within oneself; struggle for decency and goodness on the social level; and struggle on the battlefield, if and when necessary.