The scholars must "highlight the dangers which extremism poses to the Muslim's creed and conduct," he told the opening session of a conference of the Islamic Jurisprudence Assembly in the holy city of Makka on Saturday.
In an address read on his behalf, the ailing monarch said scholars had to join hands to "correct the flaws in the thinking of some Muslims through dialogue in seminars, conferences and via the media". The scholars should use religious arguments to shoot down "aberrant individual fatwas," Fahd said in a reference to religious edicts issued by dissident Saudi and other clerics that legitimise violence.
The Saudi monarch argued that some "terror organisations have taken advantage of the fact that some youths are ignorant of the true tenets of religion and enlisted them" to engage in acts of killing and violence, Fahd said.
Following the king's call, a high-profile Saudi cleric who previously aired hardline views, became the third dissident leader in three weeks to denounce a deadly bombing in Riyadh.
"The self assessment period that we went through in jail and the events that followed led us to conclude that we have committed an error and we ask God's forgiveness and the guidance of the leading scholars," said Shaikh Ahmad bin Hamud al-Khalidi in an interview with Shaikh Ayid al-Qarni aired on Saudi state television.
The cleric withdrew the edicts that had sanctioned resisting and fighting Saudi security authorities, who have launched massive manhunts and arrested hundreds in a crackdown on armed dissidents.
Asked how he viewed the 8 November attack on the Al-Muhaya compound in Riyadh which killed at least 17 people and wounded more than 120, Khailidi said: "it struck me like a bolt of lightning... one could not understand how the blood of Muslims could be spilled this way."
King Fahd says the scholars
"Those who have killed Muslims have committed a severe crime," he added to the nodding approval of al-Qarni who congratulated Khalidi for his repentance.
al-Khalidi's U-turn comes after fellow clerics Shaikh Ali bin Khudair al-Khudair and Shaikh Nasir bin Hamad al-Fahd also repented separately in mid-November, withdrawing religious edicts and support for 19 al-Qaida suspects on state television.
All three were arrested and later released for supporting Saudi dissidents wanted by the authorities.
A total of 52 people have died in suicide bombings of residential compounds in Riyadh in May and November,
prompting a crackdown by Saudi security forces on Islamist groups and fighters that has netted hundreds of suspects.
However a leading Saudi disident poured scorn on King Fahd's comments. Muhammad al-Masari told Aljazeera.net that the monarch should go back to the drawing board and examine his own relationship with Islam before advising others.
"King Fahd is desperate to hold on to his position and will do anything he can to protect himself. It's the king who is going against the teachings of Islam by allowing the US army onto the soil of Saudi Arabia and backing the war in Iraq", said al-Masari.
"I think he needs to practise what he preaches rather than dictating to others what they should preach," he added.