In this section, Allah lays down the rules of war for the religion of peace.
The first rule is that you must "fight in the way of Allah," but only against those that fight against you, and, even then, you can't start the war yourself. So preemptive war is out for Muslims.
Fight in the way of Allah against those who fight against you, but begin not hostilities. Lo! Allah loveth not aggressors. 2:190
I'm confused by the next verse, though. "Slay them wherever you find them." Who is the "them" here? Disbelievers? Those that "persecute" Muslims? Soldiers and civilians? In warfare and in acts of terrorism?
And slay them wherever ye find them, and drive them out of the places whence they drove you out, for persecution is worse than slaughter. ... Such is the reward of disbelievers. 2:191
But whomever it is that Allah wants you to kill, you're supposed to stop killing them if they stop doing whatever it was (fighting with you, persecuting Islam, being disbelievers?) that you were busy killing them for. Allah is Forgiving, Merciful, Confusing.
But if they desist, then lo! Allah is Forgiving, Merciful. 2:192
Or maybe not. Now Allah says that you must keep fighting until there is no more persecution and everyone on earth is a Muslim. Then you can stop killing people.
And fight them until persecution is no more, and religion is for Allah. 2:193a
Well, not quite, I guess. If there are any wrong-doers around after you've killed off all the disbelievers, persecutors and aggressors, then you'll have to kill them too.
But if they desist, then let there be no hostility except against wrong-doers. 2:193b
Whatever nasty stuff people do to you in war, you must do to them. Rape for rape, genocide for genocide, torture for torture. Allah is with those who fight evil with evil.
The forbidden month for the forbidden month, and forbidden things in retaliation. And one who attacketh you, attack him in like manner as he attacked you. Observe your duty to Allah, and know that Allah is with those who ward off (evil). 2:194
Always remember that "warfare is ordained for you." Allah wants you to fight in wars. You probably don't want to, but Allah thinks it's good for you. And Allah knows best.
Warfare is ordained for you, though it is hateful unto you; but it may happen that ye hate a thing which is good for you, and it may happen that ye love a thing which is bad for you. Allah knoweth, ye know not. 2:216
It's you and your religion against them and theirs. They won't stop fighting until they make you a "renegade from your religion" and if they succeed in that so you die in disbelief, Allah will burn you forever in the Fire.
... persecution is worse than killing. And they will not cease from fighting against you till they have made you renegades from your religion, if they can. And whoso becometh a renegade and dieth in his disbelief: such are they whose works have fallen both in the world and the Hereafter. Such are rightful owners of the Fire: they will abide therein. 2:217
So get out there an fight in the way of Allah
(or he'll burn you forever in the Fire after you die).