The criteria that certain commentators use to insist on calling ISIS “Islamic” would also render the khawarij “Islamic.” The same thing that made the khawarij not Islamic is the same thing that makes ISIS not Islamic. They broke with the jama`a and turned against the body of the Muslim community, made takfir against them, and even committed acts of terror and murder against them and their leaders. This may have no significance for Western academics and political commentators. But, according to our normative tradition and the logical core of “ahl as-sunnah wa al-jama`a,” such acts are enough to render one’s movement, group, and ideology cleanly outside the bounds of what is Islamic.
A group can cite classical Islamic texts till the cows come home. To concede that ISIS is Islamic on such a basis is stupid and feckless. Certainly, the khawarij were citing the Quran and hadith against Ali (r) and the other Companions. So what? Being “Islamic” is not a meaningless label that we can throw around or discard, as some Muslims who should know better seem to believe these days. For Muslims to determine that something is “Islamic” means that it is coming from God and His Messenger ﷺ. Our classical tradition is “Islamic” not because it is really, really old and whoever can cite from that tradition ipso facto becomes “Islamic” by association. It is a principle of our religion that the jama`a of Muslims reflects the will of God in a special way, so when a group breaks from that jama`a, they are thereby no longer Islamic, no matter whatever else.
Obviously, for those who don’t believe in God and aren’t Muslims and/or don’t recognize this concept of jama`a and its significance, none of this will make sense and they will continue to be confused about ISIS and ISIS’s connection to Islam. But let’s get one thing straight: The rest of us are not confused. Nor are we unprincipled, un-nuanced “cotton candy” Muslims. Nor do we suddenly think Islamic jurisprudence needs to be reformed and the classical tradition should be foregone for fresh, maqasid-based reasoning just because some idiots commit atrocities in the name of our classical scholars.