We Are At War

Well no duh.
In 2002 Osama bin Laden in his "letter to the American people"
1. The first thing that we are calling you to is islam.

Well according the to quran he has to do that to follow the words of MO. Here are the three choices we get. Fight in the name of allah and in the way of allah. Fight against those who disbelieve in allah. Make a holy war....When you meet your enemies who are polytheists, invite them to three courses of action. If they respond to any one of these, you also accept it and withhold yourself from doing them any harm. Invite them to accept islam; if they respond to you, accept it from them and desist from fighting against them....If they refuse to accept islam, demand from the the Jizya(the poll-tax on non muslims). If they agree to pay, accept if from them and hold off your hands. If they refuse to pay the tax, seek allah's help and fight them.

Sura 9:5 Once the Sacred Months are past, (and they refuse to make peace) you may kill the idol worshipers when you encounter them, punish them, and resist every move they make. If they repent and observe the Contact Prayers (Salat) and give the obligatory charity (Zakat), you shall let them go. GOD is Forgiver, Most Merciful.

OK so you think I am cherry picking well no I am no.
Imam Jala al-Din Muhammad ibn Ahmad al-Mahalli (1389-1459) and Jalal al-Din (1445-1505) asserts that the ninth sura "was send down when security was removed by the sword" Say that the 9th Sura abrogates no fewer than 124 more peaceful and tolerant verses of the quran. Another commentator Isma'il bin Amr Kathir al Dimashqi (1301-1372) declared that sura 9:5 abrogated every agreement of peace between the prophet and any idolater, every treaty, and every term...No idolater had any more treaty of promise of safety since surah bara'ah (the ninth) sura was revealed.

Here is how the muslems are expected to fight.
sura 47:4 If you encounter (in war) those who disbelieve, you may strike the necks. If you take them as captives you may set them free or ransom them, until the war ends. Had GOD willed, He could have granted you victory, without war. But He thus tests you by one another. As for those who get killed in the cause of GOD, He will never put their sacrifice to waste