Types of Defense in Islam

One of the points that now comes into question is the Islamic view of the essence and quiddity of jihad. On this point there is complete agreement amongst researchers; the essence of jihad is defense, meaning that not one of them even suspects jihad, or any kind of fighting, that is motivated by aggression, by lust for the wealth and riches and other resources of the other side, for an aggressor's harnessing of a people's economic or human resources, to be in any way permissible in the view of Islam. In Islam, fighting based on such motives are types of zulm, types of tyranny and oppression. Jihad is only for the sake of defense, and in truth, it is resistance against transgression, and can certainly be lawful. Of course, there is also the third possibility that one fights not for the sake of aggression, nor in defense of oneself or of a human value, but for the expansion of a human value, and this will be discussed later. Leaving this point aside, however, we see that in the basic definition of jihad, there is no difference of opinion and all the researchers are agreed that jihad and war must be for the sake of defense. The differences of opinion that do exist are minor ones, and concern the question of what it is that has to be defended.
The opinions of some on this matter are limited. They say that defense means self-defense; that war is lawful for an individual, a tribe or a nation in defense of itself and its life. According to this, if the lives of a people are exposed to danger from another region, then fighting in defense of their lives is lawful for that people. In the same way, if their property is subject to aggression, then from the point of view of human rights, they have the right to defend that property which is their right. Likewise, if a people is faced with the aggression of another nation that wants to take possession of its wealth and perhaps carry it away, then that people has the right to defend its wealth, even by force.
"Al-maqtulu duna ahlihi wa 'iyalihi shahidun."
Islam tells us that whoever is killed for his property or chastity is a martyr.(3) So, in Islam, defending one's chastity, is like defending one's life and property. In fact it is superior. It is the defense of one's honor. For a nation, to defend its independence, is undeniably lawful. So when a group wants to take away the independence of a nation and place that nation under its own mandate, if the people of that nation decide to defend themselves and pick up the gun, this action is lawful, in fact laudable and worthy of admiration. So, defense of life, defense of wealth, property and lands, defense of independence, defense of chastity, all these are lawful defenses. No one doubts the fact that in these cases, defense is permissible and as we have said, the view that some Christians put forth about religion having to advocate peace and not war, and that war is absolutely bad and peace is absolutely good, has no logical or reasonable basis to support it. Not only is fighting for the sake of defense not wrong, but it is extremely correct in this case to fight and one of the necessities of human life. This is what is meant in the Holy Quran when we are told:
«If God did not prevent mankind some with others, the earth would become full of corruption.» (2:251)
or again: «If God did not prevent people, some with some (others), then cloisters, churches, synagogues, and mosques in which the Name of God is oft brought to mind, would have been destroyed.» (22:40)
Up to this point all the scholars are more or less in agreement.
Martyr Murteza Mutahhari
al-islam.org