President Anwar Sadat, political descendant of the pharaohs, invoked the works of the Hebrew prophet Isaiah yesterday as well as those of John F. Kennedy in bringing his campaign of media diplomacy to Washington.

It was in the National Press Club, the ritual chamber of the Washington journalistic establishment, that Sadat conducted his bold act of courtship of American hearts and minds for his vision of peace in the Middle East.

Whatever transpired between President Sadat and President Carter in the solitude of Camp David is known only to them and the small party of aides who took part in their weekend of retreat.

But the message that Sadat projected publicly yesterday in eloquent and carefully articulated sentences was utterly clear to the audience of journalists, congressional foreign policy leaders and administration officials that crowded into the press club.

That message: if there is to be peace in Holy Land it will require the force of American public opinion being brought to bear on an increasingly intransigent Israel.

It was a message that the delivered with the skill of a master politician, in the forebearing tones of a peacemaker now faced with an obdurate antagonist. The Sadat who defied decades of hatred by going to Jerusaleum was now in Washington challenging what he acknowleged to be the "special relationship" between the United States and Israel.

"We do not want to cause you any problems, but we need your help to settle our problem," said Sadat. ". . . We are not asking you to take sides or be partial. You are expected merely to be faithful to your own tradition and values."

No longer, he declared to the press club audience, is the role of the United States in the early months of his involvment in the events of the Middle East.

Now, said Sadat, "you are a full partner in the establishment of peace . . . You can insist that disputes should be settled through compliance with the rule of law, not by submission to the dictates of force."

The Egyptian president had honeyed words for Carter, with whom he had just spent two days surveying the knotty range of problems still lying in the path of settlement.

"He has been very helpful and understanding," Sadat said of Carter. "He is a man of wisdom and courage. I enjoy dealing with him. I told him in our talks at Camp David that we urge him to continue to play a positive role in the interests of both parties."

Yet there was no hint of what progress he and the American president made on such unyielding points of dispute as the Israeli settlements in the occupied territories, the establishment of a Palestinian state, the quest by both sides for American arms, the question of regaining full Arab sovereignty in conquered lands.

These are the stakes for which Sadat is gambling in this next audacious installment of his shock diplomacy.

His crowded itinerary yesterday included meetings, following the press club speech, with leaders of American Jewish opinion and then with "senior writers and chief editors" at Blair House.

One factor that Sadat had not counted on and even Carter was unable to influence was the driving snow that clogged Washington traffic yesterday evening at the hour of his second meeting with Washington's journalistic elite.

I. F. Stone, the maverick pamphleteer who has been an important American intellectual influence for conciliation in the Middle East, started for the Blair House meeting and had to turn back on the icy wastes of upper Connecticut Avenue.

But Sadat pursued his evangelical mission with those either within walking distance or with snow tires.