What should be done against ISIS is to engage in an intellectual struggle. If you attempt to respond them with communism, if you attempt to stand against the ideology of ISIS with a Godless, Bookless, irreligious, faithless ideology, they would rout you; but if you respond to them with Islam, with the Qur'an and if you criticize the system of idolatry while doing so, you would then be successful anyway. - Harun Yahya