President Hosni Mubarak of Egypt has ordered a halt to the war of words with Syria. The Egyptian leader has asked newspaper editors in Cairo not to criticize Syria in their columns. And in recent public pronouncements he has supported Syria's claim that, unlike Israel, it had not invaded Lebanon but had been asked in by the Arab League.
Senior Egyptian officials say Mr. Mubarak's conciliatory moves toward Syria - the Arab world's harshest critic of Egyptian policies since the late President Anwar Sadat visited Jerusalem in November 1977 - are aimed at preventing further isolation of Syria within Arab ranks.
Most Arab states appear to have chosen a stand of quiet support of the US-sponsored Israeli-Lebanese agreement on the withdrawal of all foreign forces from Lebanon or have decided simply not to interfere. Syria vehemently opposes the accord and argues that it rewards Israel for last year's invasion of Lebanon.
Egyptian officials believe Syria may wish to use Egypt as an intermediary in contacts with both the United States and Israel over an agreement on Lebanon acceptable to the government in Damascus.
Informed Egyptian sources point out that Syria and Egypt have recently had direct high level contact for the first time since the signing in 1978 of the Camp David accords. Syria, according to these sources, is demanding both political and economic rewards for its possible acceptance of the Israeli-Lebanese agreement. These rewards include:
* Financial compensation for the cost of its intervention in Lebanon since 1976. Syria is reported to have told Saudi Arabia that its presence in Lebanon has cost the Damascus government $24 billion until now. Reports circulating in Cairo say that the kingdom is willing to grant Syria $12 billion.
* US guarantees for the future of the Israeli-occupied Golan Heights. President Reagan's message to Syrian President Hafez Assad two months ago, reaffirming that United Nations resolution 242 is applicable to the Golan Heights, is viewed by Arab diplomats as a first step which must be followed by firmer promises.
* Involvement of the Soviet Union in future efforts to resolve the Palestinian issue. Western diplomats compare Syrian-Soviet relations to the ties between the United States and Israel. But Syria, convinced that the US is biased toward Israel, believes that Soviet participation in future peace efforts will strengthen the Arab negotiating position.
* Security arrangements in Lebanon's Bekaa Valley similiar to those granted to Israel in south Lebanon. These arrangements include joint inspection patrols, exchange of intelligence, and control of who enters the security zone.
Both Egyptian and Arab officials say Syria has much to gain from its opposition to the Israeli-Lebanese agreement. But they warn that Syria stands to lose its possible achievements if it continues its opposition for much longer.