"The greatest affliction to strike the nation of Islam came from some of its own sons, who were lured by the devil. They have called the nation infidel, they have shed protected blood and they have spread vice on Earth, with explosions and destruction and killing of innocents," al-Sheikh said.
Al-Sheikh pointedly asked of Muslim youth: "How would you meet God? With innocent blood you shed or helped shed?"
The fact that Saudi Arabia's top cleric delivered the sermon during the climax of the annual hajj pilgrimage -- which is attended by Muslims from some 70 countries -- is seen as adding to its significance.
Faisal Ali, an editor with Saudi Arabia's main English-language daily "Arab News," is in Mecca covering the hajj. He said al-Sheikh told the world that Islam is a religion of peace and tolerance.
"This sermon by the grand mufti was aimed at those youth who have been lured by such extremist ideologues, people like Al-Qaeda, people like Ansar Islam, those who propagate and promote the militant version of Islam. Islam is not a religion which propagates militancy, so yesterday's sermon by the grand mufti was aimed to give a message to the world that, no, Islam doesn't preach any violence. Islam is a religion of peace," Ali said.
Saudi Arabia has been battling attacks by militants affiliated with Al-Qaeda. More than 100 people have been killed, many of them foreigners, since May 2003. Massive security measures have been put in place by Saudi officials to secure the hajj from possible terrorist attacks.
Dr. Mai Yamani is an expert on Saudi Arabia with the U.K.-based Chatham House, formerly known as the Royal Institute of International Affairs. She believes al-Sheikh's sermon was primarily aimed against Saudi militants who have waged a war aimed at destabilizing the Saudi regime.
"He was talking primarily for Saudi Arabia and to defend the Saudi regime because this is his job, and this is his ultimate aim -- to remain in power and the Al-Saud [Saudi royal family] are protected. Certainly, violence in the next-door countries would be very bad for Saudi Arabia because, as we know, the borders are very porous, and you have Saudis going back from Iraq, or into Iraq, the flow of arms. So certainly he means violence among Muslims in Muslim countries, but they are much more preoccupied about the stability of the Saudi regime," Yamani said.
She believes the antiterror message by al-Sheikh will have an impact only on moderate Muslims. "The message will have an impact on any human being who does not want to see violence and terror. But it stops there," Yamani said.
Ali of "Arab News" -- who was present when al-Sheikh delivered his sermon -- said many Muslim pilgrims believe the sermon will help improve the image of Islam in Western countries.
"It was given on the hajj day, which is revered by all Muslims, so it has an impact, of course. It impressed a lot of people. And those millions of Muslims who converged on Mount Arafat to perform one of the most important rites of the hajj, they were impressed by the sermon. And I talked to a lot of people, and they all agree that the grand mufti's sermon was in a very good spirit, and it will certainly dispel some of the perceptions which has been created in the West by some of the actions of these people [Islamic militants]," Ali said,
However, al-Sheikh also warned against campaigns launched by the outside world against Muslims. He said there are "military campaigns, thought campaigns, economic campaigns, and media campaigns."
He urged pilgrims to abide by the words of God and the Prophet Muhammad and not to be "fooled by a civilization known for its weak structure and bad foundation."
Yamani said Muslim militants also talk of the clash of civilizations and of Muslims being under attack from non-Muslims.
"The Hajj (Part 1) -- A Look At The History, Rituals, And Meaning Of The Pilgrimage"
"The Hajj (Part 2) -- Increasing Numbers Of Younger Pilgrims Are Making The Journey"
"The Hajj (Part 3) -- Complaints Of Bribery, Corruption, Price-Gouging Taint Religious Pilgrimage"
"The Hajj (Part 4) -- Pilgrims Dismiss Terror Fears Amid Saudi Security Deployment"
"Hajj Reaching Climax Under Tight Security Measures"