When President Carter sits down with the leaders of Israel and Egypt at Camp David this week to discuss Middle East peace, there will symbolically be two empty chairs in the conference room. They belong to two Arab monarchs whose influence on and importance to American strategy make them silent partners in the talks.

The two absent rulers are King Hussein of Jordan and King Khalid of Saudi Arabia. They separate reactions to the summit's outcome will instantly become factors in the prospects for peace or renewed Arab-Israeli hostility.

A major breakthrough at Camp David could bring Hussein into the negotiations that Egyptian President Sadat launched with Israeli Prime Minister Menachem Begin and which Carter is now attempting to save.

Failure would mobilize the oil and monetary power Saudi Arabia exercises into efforts to rebuild Arab unity at an Arab summit. Failure also means new pressure on the moderate and conservative Arab governments the Carter Administration is determined to preserve and ultimately new pressure on oil supplies and prices for industrialized nations.

Carter asked for diving guidance and help "particularly this week" during a brief prayer he offered at the end of a Sunday school lesson yesterday at the First Baptist Church here. He then attended a special 25-minute prayer session where a Christian pastor, a Jewish rabbi and the Moslem director of Washington's Islamic Center prayed for success at the summit.

From the Carter's administration's point of view, perhaps the most encouraging result of the summit would be movement by Begin to end Israeli occupation of the West Bank territory of the Jordan River that would enable Hussein to join a set of future negotiations that Carter hopes will grow out of the Camp David talks.

In an interview televised in parts of the United States yesterday by ABC-TV, King Hussein said he might reconsider his refusal to join the talks if Camp David produces "a statement of principles" that would be "clear enough" to prepare the ground for a final settlement the West Bank.

"I am sure that other Arabs would do the same, including the Palestinians," he said. But he indicated that he did not think the chances for success were good, and held out the prospect of revolutions against Arab rulers friendly to the United States as the long-term result.

Hussein ruled the territory, inhabited by l million Palestinians, until the Israelis occupied it in the 1967 Arab-Israeli war and began implanting population settlements, some of which are intended to be permanent.

Sadat teels exposed to Arab criticism in conducting negotiations alone with the Israelis. To get Hussein into the talks, he feels he needs to get Begin to agree to a set of broad principles that will commit the Israelis to ultimately returning the West Bank and the Gaza Strip, Syria's Golan Heights and Egypt's Sinai peninsula to Arab sovereignty.

Begin, who arrived in New York yesterday, has indicated that Sadat could have all of the Sinai back immediately if he agrees to a final bilateral peace. Syria's strong condemnation of the negotiations that have grown out of Sadat's journey to Jerusalem last November has left the Golan Heights issue on the sidelines of Camp David.

For emotional, religious and security reasons, Begin has refused to consider a commitment to return all of the West Bank, which he calls by the Biblical names of Judea and Samaria. U.S. officials suggests indirectly that Carter will devote much effort to emphasizing to Begin that the Palestine Liberation Organization, which has given responsibility for the West Bank and Gaza at the Arab summit in 1974, has been so weakened since then that it no longer represents a threat to Israel and that the danger of a radical Palestinian state emerging from the West Bank has greatly lessened.

Agreement on a negotiating principle for the West Bank and Gaza could open the way not only for Hussein to enter peace talks but also for a Palestinian presence at future negotiations.

Israeli Knesset member Salman Choval who is close to Foreign Minister Moshe Dayan, said in a conversation in Washington last week that a compromise could probably be reached between Israel's previously stated willingness to let Palestinians living in the West Bank and Gaza participate in the determination of their future, and Egypt's insistence that all Palestinians, including several million refugees, be involved in that determination.

Procedurally, Choval said, a new position could emerge from efforts to reconcile at Camp David the U.S.-Israeli working paper adopted last October and the Aswan declaration on "the legitimate rights of the Palestinian people" issued by Carter and Sadat in January.

The Saudi role in the negotiations continues to be a behind-the-scenes, ambivalent and vital one, for all participants. Like Hussein's reactions, King Khalid's responses have already helped determine American strategy a key factor in the situation that develops afterward.

One measure of the importance that the Carter administration accords to the world's largest oil exporter is that Khalid was evidently the first foreign leader to be informed that the summit would happen. John C. West, U.S. ambassador to Saudi Arabia, was flown to Alexandria to be told by Secretary of State Cyrus R. Vance, and then hurried back to tell Khalid before the summit was announced.

One indication of how the summit is going could be when Sadat feels he needs to consult with or advise the Saudis, who provide several billion dollars each year for the sagging Egyptian economy and military forces. He would probably do so during the summit only if a major change occurred.

The Saudis have become increasingly pessimistic about Sadat's ability to get concessions from Begin by carrying on direct negotiations. U.S. officials believe the Saudis still support Sadat and see no immediate alternative to peace efforts, but that they have become more concerned now about Syria's reaction to the stalled solo performanie by Sadat.

Maintaining strong influence over Syria is almost as important a goal for the Saudis as is maintaining close ties with Sadat. The Saudis attempt to balance those two goals, and have found it increasinly difficult because of Sadat's initiative with the Israelis.

In yesterday's interview, Hussein said that "days" before Sadat launched his surprise initiative last November, Hussein, Syrian President Hafez Assad and King Khalid had reached agreement with Sadat on a plan to resume the stalled Geneva peace conference on the Middle East with a joint Arab delegation and negotiating position.

Immediately before Vance went to the region on Aug. 5 to arrange the Camp David summit, American officials confirmed that Saudi Arabia was attempting to convene an Arab summit that would in effect formally bury the Sadat Jerusalem initiative, bring the Egyptian back into the Arab political fold and launch a new, joint Arab effort to get American pressure on Israel to produce a peace agreement.

Crown Prince Fahd was publicly welcomed Carter's "courageous" decision to call the summit. Some U.S. officials feel that the Saudis have merely shelved their plans to call a meeting of Arab leaders and to begin preparing to go back to Geneva until they see if the summit produces some maneuvering space for Sadat.

Begin and Sadat will arrive in Washington tomorrow and will travel by helicopter to Camp David, where the talks with Carter are expected to begin Wednesday morning. Begin and Egyptian officials have told reporters that the conference will go to Sept. 12 and perhaps beyond.