Reagan to Begin: concern, not rebuke

The widely publicized ''letter'' from President Reagan to Israeli Prime Minister Menachem Begin was in fact an ''oral message'' which left more questions unanswered than it addressed, according to officials here in a position to know its content.

The message urged the Israeli leader to help maintain a cease-fire around Beirut and to allow the flow of food, water, power, and electricty to west Beirut. Delivered by Samuel Lewis, the US ambassador to Israel, Reagan's remarks expressed concern that Israeli actions around Beirut were hindering the negotiating efforts of Philip C. Habib, the American special envoy in Lebanon. The Israelis had apparently at one point blocked the movement of Lebanese muslims acting as intermediaries between the Palestine Liberation Organization and Habib. The President noted this with displeasure, say the officials.

Did the memo threaten that the US might talk directly with the PLO? Officials denied that the US is engaging in any ''diplomacy by threat.'' But the administration seems to be moving toward acceptance of the idea put forward by Saudi Arabia and other key Arab nations that a failure to resolve the Palestinian problem is a leading cause of Middle East instability.

At the opening of his confirmation hearings before the Senate Foreign Relations Committee on July 13, Secretary of State-designate George P. Shultz said that the crisis in Lebanon had dramatized an urgent need to address the Palestinian problem in all its dimensions. New stress on the Palestinian issue by the administration could lead to a period of tension, if not confrontation, between the United States and Israel.