Shut up.

Back in the day (623 AD), Muslims killed Infidels (that would be pagans, polytheists, and fellow monotheists who were practicing their religions long before Mohammed had his vision - that would be Jews and Christians, for those of you who haven't been paying attention) who refused to convert to Islam. In those days they used the sword and arrow and other tactics that became popular in the Middle Ages.

Today, Muslims are killing Infidels with suicide bombs, truck bombs, car bombs, donkey bombs, IEDs, RPGs, and assorted rockets, when they're not trying to use even bigger trucks and explosives on airplanes.

Until Muslims start protesting these killings, they should shut up and take a good look in the mirror, instead of getting upset because the Pope quoted a medieval text referring to their earlier terrorist acts.

"We are destined to be a barrier against the return of ignorance and barbarism" wrote Thomas Jefferson, the first American president to stand up to Islamic terrorists, the Barbary "Pirates". (The French, of course, kept paying ‘tribute’ to them. Funny how some things never change…)