Robert Fisk: We have long ago lost our moral compass, so how can we lecture the Islamic world?

Responding to a comment of mine - to the effect that "deep down" we do, however wrongly, suspect that religion has something to do with the London bombings - Mr Shepherd gently admonishes me. "I wonder if there may be more to it than that," he remarks. And I fear he is right and I am wrong.

His arguments are contained in a brilliantly conceived article on the roots of violence and extremism in Judaism, Christianity and Islam - and the urgent need to render all religions safe for "human consumption".

Put very simply, Mr Shepherd takes a wander through some of the nastiest bits of the Bible and the Koran - those bits we prefer not to quote or not to think about - and finds that mass murder and ethnic cleansing get a pretty good bill of health if we take it all literally.

The Jewish "entry into the promised land" was clearly accompanied by bloody conquest and would-be genocide. The Christian tradition has absorbed this inheritance, entering its own "promised land" with a ruthlessness that extends to cruel anti-Semitism. The New Testament, Mr Shepherd points out, "contains passages that would ... be actionable under British laws against incitement to racial hatred" were they to be published fresh today.

The Muslim tradition - with its hatred of idolatry - contains, in the career of the Prophet, "scenes of bloodshed and murder which are shocking to modern religious sensibilities".

Thus, for example, Baruch Goldstein, the Israeli military doctor who massacred 29 Palestinians in Hebron in 1994, committed his mass murder on Purim, a festival celebrating the deliverance of the Jewish communities from the Persian empire which was followed by large-scale killing "to avenge themselves on their enemies" (Esther 8:13).

The Palestinians, of course, were playing the role of the Persians, at other times that of the Amalekites ("... kill man and woman, babe and suckling, ox and sheep, camel and donkey" - 1, Samuel 15:1, 3). The original "promised land" was largely on what is now the West Bank - hence the Jewish colonisation of Palestinian land - while the coastal plain was not (although suggestions that Israel should transplant itself further east, leaving Haifa, Tel Aviv and Ashkelon to the Palestinians of the West Bank are unlikely to commend themselves to Israel's rulers).

The "chosen people" theme, meanwhile, moved into Christianity - the Protestants of Northern Ireland, for example, (remember the Ulster Covenant?), and apartheid South Africa and, in some respects, the United States.

The New Testament is laced with virulent anti-Semitism, accusing the Jews of killing Christ. Read Martin Luther. The Koran demanded the forced submission of conquered peoples in the name of religion (the Koran 9:29), and Mohammed's successor, the Caliph Abu Bakr, stated specifically that "we will treat as an unbeliever whoever rejects Allah and Mohammed, and we will make holy war upon him ... for such there is only the sword and fire and indiscriminate slaughter."

So there you go. And how does Mr Shepherd deal with all this? Settlement policy should be rejected not because it is theologically questionable but because the dispossession of a people is morally wrong. Anti-Semitism must be rejected not because it is incompatible with the Gospels but because it is incompatible with any basic morality based on shared human values.

If Muslim violence is to be condemned, it is not because Mohammed is misunderstood but because it violates basic human rights. "West Bank settlements, Christian anti-Semitism and Muslim terrorism ... are not morally wrong because theologically questionable - they are theologically questionable because morally wrong."

And it is true that most Christians, Jews and Muslims draw on the tolerant, moderate aspects of their tradition. We prefer not to accept the fact that the religions of the children of Abraham are inherently flawed in respect of intolerance, discrimination, violence and hatred. Only - if I understand Mr Shepherd's thesis correctly - by putting respect for human rights above all else and by making religion submit to universal human values can we " grasp the nettle".

Phew. I can hear the fundamentalists roaring already. And I have to say it will probably be the Islamic ones who will roar loudest. Reinterpretation of the Koran is such a quicksand, so dangerous to approach, so slippery a subject that most Muslims will not go near.

How can we suggest that a religion based on "submission" to God must itself "submit" to our happy-clappy, all-too-Western " universal human rights"? I don't know. Especially when we " Christians" have largely failed to condemn some of our own atrocities - indeed, have preferred to forget them.

Take the Christians who massacred the Muslims of Srebrenica. Or take the Christians - Lebanese Phalangist allies of the Israelis - who entered the Sabra and Chatila refugee camps in Beirut and slaughtered up to 1,700 Palestinian Muslim civilians.

Do we remember that? Do we recall that the massacres occurred between 16 and 18 September 1982? Yes, today is the 23rd anniversary of that little genocide - and I suspect The Independent will be one of the very few newspapers to remember it. I was in those camps in 1982. I climbed over the corpses. Some of the Christian Phalangists in Beirut even had illustrations of the Virgin Mary on their gun butts, just as the Christian Serbs did in Bosnia.

Are we therefore in a position to tell our Muslim neighbours to "grasp the nettle"? I rather think not. Because the condition of human rights has been so eroded by our own folly, our illegal invasion of Iraq and the anarchy that we have allowed to take root there, our flagrant refusal to prevent further Israeli settlement expansion in the West Bank, our constant, whining demands that prominent Muslims must disown the killers who take their religious texts too literally, that we have long ago lost our moral compass.

A hundred years of Western interference in the Middle East has left the region so cracked with fault lines and artificial frontiers and heavy with injustices that we are in no position to lecture the Islamic world on human rights and values. Forget the Amalekites and the Persians and Martin Luther and the Caliph Abu Bakr. Just look at ourselves in the mirror and we will see the most frightening text of all.