If ever Israel needed to use restraint, it is now. Prime Minister Ariel Sharon, ever quick to order retaliation against attacks by Palestinian rebels, must this time - in the name of peace - refrain from over-reacting. Retaliation has become Mr Sharon's only weapon to fight the deadly attacks, but it is a strategy which in the past few months has drawn Arabs and Jews further apart than they have been for decades. Suicide bombings were met with missile and helicopter gunship strikes on suspected targets of the extremist Palestinian groups Hamas and Islamic Jihad and the offices of Palestinian leader Yasser Arafat. Mr Sharon's tactics appeared to be working after Mr Arafat, virtually a prisoner in his own territory, called a ceasefire. American envoy Anthony Zinni, recalled by Washington at the height of the bloodshed, returned to the region last week and it seemed US peace plans could finally be initiated. The killing of four Israeli soldiers by two Palestinian gunmen on a kibbutz adjacent to the Gaza Strip yesterday could not have come at a worse time. Although both gunmen were shot dead, their attack has instantly shattered a sense of stability that had begun to permeate the conflict. Too many lives have been lost on both sides and memories are long. While Judaism teaches peace, and many ordinary Israelis wish for an end to the bloodshed, they also realise that their state and their lives are in danger if they do not protect it. Palestinians, feeling trapped and claiming their land is being stolen, are becoming increasingly militant. A rising number are prepared to die in the name of their struggle. But Mr Arafat and his security forces cannot possibly monitor every Palestinian. Mr Sharon must realise that if he orders his military to take up where it left off, months of efforts to get talks restarted will be lost. But this time, he will also endanger American involvement and hopes for peace in the lifetimes of Israelis and Palestinians.