NEW YORK -- Israelis spent decades dismissing the words of Yasser Arafat as meaningless and false. Now they take those words more seriously than the PLO chairman does himself. And so they should.

In a May 10 speech in a Johannesburg mosque, Arafat called for a "jihad" to liberate Jerusalem. He then suggested that his peace agreement with Israel was only a tactical step that could still be reversed. These words touched off a political firestorm in Israel. Officials there say Arafat's remarks call into question the Palestine Liberation Organization's commitment to peace.

Arafat's advisers offer slippery explanations of what their boss meant to say: He did not intend "jihad" as holy war, its customary usage. He was calling for a nonviolent campaign of liberation of Jerusalem. His reference to a peace treaty abandoned before the forces of the Prophet Mohammed took Mecca has been distorted by the Israeli media; Arafat was actually showing that Muslims keep their commitments.

Pardon my Arabic: Hogwash.

Arafat knew how his words would be interpreted by South African Muslims unless he specified alternative, lesser- known meanings. The PLO spin control squad explains that words mean what they want them to mean after Arafat has uttered them in another context.

The truth is more prosaic. Arafat got caught by an unexpected tape recording that found its way to Radio Israel. He could not resist telling a Muslim audience what it wanted to hear and what in his heart of hearts he probably believes. To Muslims Arafat preaches words of struggle, while he talks of peace on the White House lawn and to the Israeli public.

This is a return to form by Arafat, who survived in Arab politics (a continuation of war by other methods) by playing off feuding Arab leaders against each other. But this time his remarks have been gleefully seized upon by Israel's right-wing Likud opposition to flail Prime Minister Yitzhak Rabin. Arafat's words wound Rabin by undermining Israeli public support for Rabin's peace efforts with the Palestinians and Syria. Rabin and Foreign Minister Shimon Peres have thus demanded that Arafat recommit himself in writing to peace.

But what good is a new pledge from Arafat if he didn't mean it the first time? Why should Israelis begin to believe this man now, after a political lifetime of manipulating words as ruthlessly as he manipulated people and causes for his own ends?

Arafat promised his people war against Israel when he could not deliver it. Now he promises Israelis peace when both his ability and his desire to deliver it have to be seriously questioned. But as events unfold, the Johannesburg mosque uproar should illustrate two essential points about the Israeli-Palestinian political accord.

The first is that Rabin and Peres are not foolish enough to depend on the word alone of Arafat. They have held back enough cards to suspend or abandon the Israeli withdrawal from the West Bank and Gaza Strip well before Israel's security is threatened by the PLO. They will not hesitate to do so. Secondly, and paradoxically, words do count and count enormously in this phase of Middle East peacemaking, as ice-breaking turns into cooperative risk-taking. Arafat should learn from his Johannesburg speech that words, once uttered, no longer belong to their speaker. They take on a weight, and a life, of their own. The context will often determine what they mean more than the speaker's intent.

That is why the Israelis need to bring Arafat back to the language of peace. He must recommit his constituency in words, and deeds, to cooperative risk-taking with the Israeli leadership.

Far more significant than Arafat's speech was a statement over the weekend from the PLO news agency, WAFA, condemning the killing of two Israeli soldiers in the Gaza Strip. WAFA correctly warned that the attack on the Israelis was in fact an attack on the Palestinian leadership and its efforts to liberate Gaza and the West Bank by peaceful means.

Those words reflect reality. Arafat's very survival in Jericho is a joint Israeli-Palestinian venture. Neither Arafat nor peace will survive the challenge of the fundamentalists and other Palestinian rebels without active, committed Israeli protection.

All the blustering and bravado in Johannesburg or elsewhere cannot change that. The new words of peace Arafat needs to utter are not really directed at Israelis, who are under no obligation to believe him. His words must be directed, clearly and expressly, to the Palestinians. They must know and accept the commitments to which his words and actions bind them.