London, England -The spiritual leader of the worldwide Anglican Communion is to appeal for people of all faiths to place their trust in God in the wake of terrorist outrages such as the July 7 attacks.
The demonstration of "extreme confidence" in God would combat the "extremists of murder and fear", the Archbishop of Canterbury Rowan Williams will say in a Sunday sermon at York Minster in northern England.
The plea follows the anniversary of the deadly July 7 suicide bombings on London, which killed 56 people and wounded about 700.
The pain of those attacks, which were carried out by four British Muslim suicide bombers, was still deeply felt, Williams was to say.
Terrorists who used religion to justify their killing were promoting a "blasphemy", Williams was to argue.
"For the person who resorts to random killing in order to promote the honour of God or the supposed cause of justice it is clear that God is too weak to be trusted.
"God is too weak to look after his own honour and we are the strong ones who must step in to help him. Such is the underlying blasphemy at work.
"What we need is that people in all communities of faith do not seek to fill the void in their souls by feverish language and action that is blind to the reality of others.
"It is people who are extreme in their confidence in God who will most effectively challenge the extremists of murder and fear.
People of all faiths had to come to terms with the "horrible fact" that there were those who want to serve their God by "organised slaughter and suicide", he will add.
Britain observed two minutes of silence on Friday in memory of the 52 people who died when the four bombers, with explosives packed into rucksacks, blew themselves up inside three packed London underground trains and a double-decker bus on July 7, 2005.
It was the worst-ever terrorist attack on British soil, as well as Europe's first experience with a suicide bombing.