Islam “dictates” that all Muslims (Meaning Muslim men) emulate Mohammed and do “exactly” as he did to the letter and since Mohammed was a brutal uncompromising War Lord that lived and practiced Jihad (war) that is what they must do to this day. Their goal today is as was Mohammed’s goal which was to rid the world of all other forms of living and make everyone in the world a Muslim or kill or enslave them. There can “never” be peace between a Muslim and anyone else (the Kafir is the proper word. Infidel is a generic word not limited to Islam) and anyone who thinks otherwise is a total fool.
In Islam there are three books and a set of laws that govern every aspect of a Muslims life and they are the Koran, the Hadith, the Sira and Sharia law. These four define what a Muslim man must do which is to be like the perfect Muslim Mohammad and since Mohammad was a War Lord —
There is no such thing as radical Islam, Islam is Islam exactly as ISIS or ISIL practices it.