The Grand Sheikh of Al-Azhar, Ahmed el-Tayeb, bears much of the responsibility for the 49 Muslim shooting victims in New Zealand and other victims of anti-Muslim violence in the West.

He has failed to clearly and unequivocally condemn the actions of groups like ISIS, Al-Qaeda, and Al-Shabaab and strip these groups and their followers of any Islamic religious legitimacy. It is past time for him to draw a clear distinction between the religious message of Islam and the violent ideology of Islamist extremism. He had a golden opportunity to do so at the interfaith meeting with the pope last month in Abu Dhabi and he failed to do so.

Lone wolf terrorism can work both ways. El-Tayeb is the only one with the religious (and moral) authority in Sunni Islam to clearly condemn the crimes of these groups and unequivocally excommunicate their followers from orthodox Islam. Violence against innocent Muslims will continue until he does exactly that.