According to Jürgen Todenhöfer who spent 10 days in the “Islamic State” last year, Israel is the only country in the world that ISIS fears. Apparently, ISIS is not intimidated by the U.S. nor the U.K., because ISIS believes they can defeat their ground troops.
ISIS has not been open about this weakness, and has even made threats against Israel and Jewish people in its propaganda videos.
So, if Israel is the only country feared by ISIS, why aren't they fighting ISIS?