"Whosoever killeth a human being... " says the Qur'an, in the 32nd verse of its fifth chapter, "it shall be as if he had killed all mankind, and whoso saveth the life of one, it shall be as if he had saved the life of all mankind."
Thus, the two supposedly Muslim men suspected of ambushing, murdering and mutilating an unarmed, off-duty soldier in the middle of a London street, while shouting "Allaho Akbar" (or "God is Great"), were brazenly violating the injunction of their own holy book. Perversely, it was the non-Muslim cub scout leader who, in trying to save the soldier's life and standing up to his alleged attackers, was acting in accordance with Qur'anic principles. Let's be clear: Islam, like every other faith, doesn't permit the killing of innocents. Armed jihad is permissible only in self-defence and if sanctioned by a legitimate government. To quote from our prime minister's pitch-perfect statement outside No 10, Wednesday's broad-daylight barbarism was "a betrayal of Islam and of the Muslim communities who give so much to our country".
Thankfully, British Muslims no longer have to wait for the much-maligned Muslim Council of Britain (MCB), or self-appointed 'community leaders', to take a public stand, nor they do need to compete with clowns like Anjem Choudary for media attention; they have been empowered by Twitter and Facebook, where in great numbers they have expressed disgust at the invoking of Islam to support such an appalling crime. (Commendably, the MCB issued a press release "unreservedly" condemning the murder as "a barbaric act that has no basis in Islam" within six hours of it occurring.)
Yet conventional wisdom still says the religion of Islam is behind violent extremism and radicalisation; that Muslims don't do enough to denounce terror; that imams and mosques incite hate and holy war. As is so often the case, the conventional wisdom is wrong. I have been a Muslim all my life and visited mosques across Europe, North America and the UK. Never, not once, have I come across an imam preaching violence against the West or justifying the murder of innocents.
Remember: the Boston bomber Tamerlan Tsarnaev was thrown out of his local mosque after lashing out at the imam for praising Martin Luther King in his Friday sermon. The Muslim father of the 'underwear bomber', Umar Farouk Abdulmutallab, approached US officials to warn them about his son, several months before the latter tried to blow up a US-bound flight in December 2009. And the car bomb planted by Faisal Shahzad in Times Square, New York, in 2010, was brought to police attention by a Senelegase Muslim street vendor who spotted smoke coming out of the vehicle.
Many of my fellow Muslims want consistency from politicians and the press. When Anders Breivik, self-styled member of an 'international Christian military order', massacred 77 innocent Norwegians, most them children, in July 2011, did we indict Christianity? Sadly, we hold Islam and Muslims to a separate standard - despite the fact that, nowadays, (self-) radicalisation tends to be an online phenomenon; what the experts call the 'third wave' of al-Qaeda-inspired extremism has no need for either UK mosques or Pakistani training camps.
"Is it even possible to stop two nutjobs from going online and radicalising themselves and then going out to kill someone on the street with kitchen knives?" an exasperated official told me yesterday morning. "How do you prevent that?" Demonising Islam or Muslims won't help.
Listen to Olivier Roy, one of Europe's pre-eminent experts on extremism: "The process of violent radicalisation has little to do with religious practice." Read the classified briefing note prepared by the MI5's Behaviourial Science Unit in June 2008. "Far from being religious zealots, a large number of those involved in terrorism do not practise their faith regularly," reported the Guardian's Alan Travis, who obtained a copy of the document. "Very few have been brought up in strongly religious households...there is evidence that a well-established religious identity actually protects against violent radicalisation."
Yet on TV news channels, on newspaper comment pages, on social networks, everyone is either a terrorism expert, an Islam expert, or both. Some cut and paste verses from the Koran out of context; others unthinkingly demand 'reform' of Islam. Few want to discuss the role of British foreign policy in helping to radicalise these young, disaffected individuals. Meanwhile, former CIA official Marc Sageman says that, "11 and a half years after 9/11, we still don't know" what turns young men towards terror.
I'll tell you this, though: it isn't my faith or the faith of 1.6billion other Muslims. For once, I'm with David Cameron.
Follow Mehdi Hasan on Twitter: www.twitter.com/mehdirhasan