Sheikh Shawky Ibrahim Abdel-Karim Allam spoke about the recent execution of a Jordanian pilot at the hands of ISIS. Lt. Moath al-Kasasbeh, 27, was burned alive while confined in a cage.
"What happened to the Jordanian pilot is by all means a crime. This barbaric action is far away from humanity, much less religions. Islam is innocent of this act," the grand mufti said on Thursday.
Allam leads Dar El-Ifta, or the House of Fatwas, the premier authority in Islamic legal interpretations. The institution was founded in 1895, although the grand muftis of Egypt have been interpreting Islam for 800 years. It releases more than 500,000 edicts a year.
The battle is ideological, Allam said, and the fight is not confined to Egypt or the Middle East.
"Violence and radicalization have become an international phenomenon that has no home or belief. But it runs through the entire world," he said.
Can beheadings ever be justified?
The pilot's death was captured in a horrific video that was posted online this week.
ISIS has distributed footage of its executions before, but previous videos showed beheadings.
The grand mufti weighed whether beheadings could ever be justified by Islam.
He considered the example of Saudi Arabia, a key U.S. ally in the region. There, defendants may be sentenced to death and beheaded.
"What happens in Saudi Arabia is based on judicial investigations and implementing the predominant law. If it is the case, then we respect the rule of law in this state," Allam said.
By contrast, he argued, ISIS does not follow any system of investigation.
"Everything ISIS does is far away from Islam. What it is doing is a crime by all means," the grand mufti said.
Tradition versus reform
Earlier this year, Egyptian President Abdel Fattah el-Sisi called for a "religious revolution."
Allam believes in the need for reform, but he also believes the foundation of Islam must remain untouched.
What does this mean?
It means "renewing the methods, renewing the tools, and renewing the way Islam's teachings are presented, " Allam said. "At the same time, we preserve and uphold the stable pillars of religion. Rattling the pillars leads to destabilizing communities."
In an effort to reclaim the voice of Islam from radical groups, Dar Al-Ifta issues publications in 10 languages, engages in awareness campaigns and joins regional and international efforts to battle extremist ideas and to present a better image of Islam.
The grand mufti's advice to young Muslims is to seek specialized scholars to understand the true meaning of Islam.
"We tell youth, Islam didn't carry a message of sabotage and destruction. It only came to serve humanity, to achieve world peace and bring mercy to the world," he said.