Therefore when you meet those who are kafir strike their necks. Then when you have decimated them, tie their bonds tightly and set them free or ransom them, until the war is finally over. That is how it is to be. If Allah willed, He could avenge Himself on them. But it is so that He can test some of you by means of others. As for those who fight in the Way of Allah, He will not let their actions go astray.