At Israel's suggestion, friendly senators have called off high-pressure action against President Reagan's imminent decision to make Saudi Arabian F15 aircraft more lethal -- the first time in years that a U.S. action not favorable to Israel will be allowed to happen without bitter controversy.

Prime Minister Menachem Begin himself is the source of the surprising Israeli government decision not to court political battle with a new, hardline Republican president who has swon fidelity to Israel. One reason for Begin's retreat from high-pressure tactics so useful in the past: Israel has far more confidence in Reagan's loyalty than in any of his recent predecessors'. That might change the U.S.-Israeli relationship for the better, giving Israel more self-confidence.

The way was cleared Feb. 4 for the usual outraged letter from pro-Israel senators warning Reagan not to give the Saudis long-range fuel pods and new armaments for their F15s, needed for self-defense in the threatened Persian Gulf. When the aircraft were sold to Saudi Arabia in 1978 in the face of a tie vote by the Senate Foreign Relations Committee, President Carter pledged they would be interceptors only -- not fitted with bomb racks and long-distance fuel capacity.

Within hours after Defense Secretary Caspar Weinberger's public statement on Feb. 3 that a decision would be made on the extra equipment for the F15s, Democratic Sen. Joseph Biden of Delaware had drafted a "Dear Mr. President" letter and was circulating it to colleagues.

But something happened on the letter's way to the Oval Office. Biden told us that the congressional recess had sent so many senators scurrying out of town that he was postponing his lobbying effort for lack of immediate signatures.

Insiders had a different explanation. They said Biden learned that the potent pro-Israel lobbying group, the America-Israel Political Action Committee, was counseling extreme caution partly on grounds that Begin's badly weakened government was uncertain how to proceed.

What worried the Israelis were two disturbing possibilites. The first was that conservative Republicans would refuse to sign any letter trying to put the arm on the new president. In the Carter presidency there was no such restraint on Republicans or Democrats.

The second reason is strategic, not tactical. Neither Begin nor his Labor Party opposition wants to get off on the wrong foot with a new president whose professions of layalty to Israel have been consistently higher than any president since Lyndon Johnson. A lobbying campaign against Reagan's first major decision involving Israel could change his mind about Israel, while failing to change his mind about sending the new equipment to Saudi Arabia.

"We just have to trust Reagan on this one," one pro-Israel insider told us. Such words would never have been spoken about Carter, who, fairly or not, was consistently faulted for failing to accept Israel's word aobut the Arab threat.

In addition to this trust of Reagan, the Israelis doubt that either Secretary of State Alexander Haig or Weinberger would bow to political pressure from the Senate on the Saudi arms deal. In sharp contrast to both of Carter's secretaries of state, Cyrus Vance and Edmund Muskie, Haig is respected in Israel as a tough strategic thinker not to be toyed with.

That means Haig looks at Israel not in terms of American constituency-group politics but as an American ally with strategic strength to offer Washington, much like Saudi Arabia and other U.S. allies in the Arab world. Haig does not intend to name a successor to the astute Sol Linowitz, Carter's special ambassador on the Egyptian-Israeli Camp David agreement. The Reagan administration sees no need for an envoy particularly acceptable both to American Jews and to Israel.

By the same token, Reagan has made a tentative decision not to hire a resident White House emissary to the American Jewish community. Reagan feels his own credentials with American Jews are good enough.

The matter of the F15s looks to Reagan and his top advisers like an ideal first test for working out a new, less paternalistic relationship with Israeli while actually strengthening the U.S.-Israeli alliance. Haig has told Israeli ambassador Ephraim Evron that Israel's stake in a peaceful Persian Gulf should be just as high as Western Europe's, Japan's and America's, and that the United States would never permit Saudi Arabia to use beefed-up F15s against Israel. Begin would not have swallowed that from Carter, but he is on the verge of accepting it from Reagan. The could open a brighter new chapter in the tortuous history of Arab-Israeil raltions.