THERE is a line early on in the Bible that encapsulates precisely the dilemma of the war in Iraq. Jacob is returning home after an absence of many years. He hears that his brother, Esau, is coming to meet him with a force of 400 men. It does not augur well. Jacob had left home in the first place because Esau was threatening to kill him. Was he now about to carry out that threat?

We read that “Jacob was very afraid and distressed”. An ancient rabbinic commentator, puzzled by the apparent repetition, made a distinction between the two emotions: “Jacob was very afraid — that he might be killed. He was distressed — that he might be forced to kill.” The first fear was physical, the second moral.

Later commentators raised a question about this interpretation. Why, they asked, should Jacob be distressed at the prospect of killing if it was to save his own life? The right to life presupposes the right to self-defence. If so, he should have had no qualms. Yet those who care for life must be distressed at any loss of life, even when justified. It is one thing to be faced with a choice between good and evil; another to be forced to choose the lesser of two evils. No decent human being takes the latter lightly. There are times when even doing the right thing involves distress.

As it happens, Jacob was not forced to choose. The brothers met in peace. The conflict with Iraq has proved more intractable. Yet despite the apparent polarisation of views for and against war, public opinion these past few months has shared much common ground.

Even those against the war acknowledge the brutality of the current Iraqi regime, its responsibility for war and massacre, the suffering it has inflicted on its own people, and the danger it represents if it has weapons of mass destruction. Even those in favour of war are mindful of the bloodshed it may cause to innocent civilians and the risk it poses of destabilising an entire region.

It has been an agonising dilemma, and the very fact that public opinion has been divided is itself a mark of how much the West has changed. We sometimes forget how enthusiastically an entire generation greeted the prospect of war in 1914. Those days are long gone. We now know that war is an evil, even if it is sometimes judged to be a necessary evil.

What therefore should be our thoughts in the days ahead? First, our prayers should be with the soldiers and their families, and with the people of Iraq, that the conflict be as short and free of casualties as possible. Every innocent life lost is a tragedy and not even the highest motives of self- defence can turn it into anything other than a tragedy.

Second, our prayers should be with the political and military leaders, who carry an immense burden of responsibility. I doubt whether any of them has been spared the inner conflict between fear and distress, torn between the twin dangers of action and inaction, knowing that whichever way they choose is fraught with risk. May God grant them wisdom, judgment and compassion.

Third, we should pray for the day after. More than 2,500 years ago, Isaiah and Micah envisaged a time when “nation shall not lift up sword against nation, neither shall they learn war any more”. Once that was a prophetic dream. The stakes are now too high for it to remain so. Finding non-violent forms of conflict resolution is the greatest single challenge facing humanity.

• Rabbi Jonathan Sacks is the Chief Rabbi of the United Hebrew Congregations of the Commonwealth