The outstanding thing about the first anniversary of the Camp David Egyptian-Israeli peace agreement is that the accord has turned out so differently from what opponents and critics prophesied.

It is no wonder that the anniversary found Egyptian President Anwar Sadat in such high spirits, for instead of being brought to his knees, as threatened by the Arab "rejectionist front," it is the rejectionist bloc, not Sadat, that is in trouble.

At the emergency Baghdad summit meetings prompted by the Camp David agreement, virtually the entire Arab world, led by Syria, Iraq, Libya and the Palestine Liberation Organization, set out to isolate, boycott and destroy Sadat. But today the Egyptian leader is stronger than ever, while the rejectionist leaders are not only divided, but also afflicted with growing and dangerous internal conflicts.

Sadat was not greatly exaggerating when on his recent state visit to Haifa he called Egypt an "island of peace" surrounded by "instability." His challenge was: "Let's see what the Arabs can do without Egypt, and what Egypt can do without the Arabs."

His comment impressed Robert Strauss, the realistic U.S. special envoy to the Middle East. "I would think that when Sadat looks around," Strauss said, "and sees what's happening to the others, he feels on the right course."

That's not the way it was supposed to be. "Sadat will be lucky if he lasts a year," predicted Ahmed Iskander, the Syrian spokesman, "and when he is gone, Egypt will repudiate its treaty with Israel." Saudi Arabia's deputy prime minister gave the peace accord an even shorter life. "In the next few months," he said, "Sadat will be persuaded to abrogate all of his agreements with the Zionist entity."

Yasser Arafat, the PLO leader, vowed to "chop off the hands of the stooge Sadat, the terrorist Begin and the imperialist Carter." The "wanton" peace pace, he said, "will be crushed under our boots." All the score or more of Arab nations, except Oman, Sudan and Somalis, cut their diplomatic ties to Egypt.

Sadat was not intimidated. From the beginning he countered with strong attacks on his Arab critics, not hesitating to challenge their integrity and political legitimacy. Some neutral observers feared he might be underestimating the determination and power of his foes to overcome him.

He knew, however, what he was doing. Today, he can ask, "What is this other camp?" In Iraq, as he points out, "the president was overthrown. In Syria, the situation is getting worse. Everything is deteriorating, especially after the Lebanese fiasco." And he adds: "In Morocco, in Algeria, in Libya, in the Gulf countries, the situation is changing, and even in Saudi Arabia people are talking about changes at the top." Moreover, both the Egyptian and Israeli governments have been getting signals suggesting that Jordan and Syria are leaning toward joining "the peace process."

Where does this leave the PLO and its demand for an independent Palestine? President Carter recently said he had "never met an Arab leader who in private professed the desire for an independent Palestinian state."

Despite the crocodile tears the Arabs publicly shed over the PLO cause, it is a telling fact that no Palestine state was established on the West Bank and Gaza when they were occupied for 20 years by the Arabs. In real life, the Arabs, with good cause, fear and distrust the PLO forces, which almost overthrew Jordan's King Hussein in 1970 and reduced Lebanon to rubble.

President Sadat's current euphoria over the progress of his peace talks with Israel's prime minister, Menachem Begin, clearly indicates that he has no intention of letting the PLO sabotage an accord that is already yielding Egypt large benefits.

For years, the advocates of a separate Israeli-Egyptian peace contended that it would make the two countries militarily impregnable and enable Egypt, freed from impoverishing wars, to get on its feet economically.

Cairo's treasury is already swelling with revenues from Suez Canal tolls and the oil fields, which will increase even more when Israel returns the remainder of the Sinai wells to Egyptian control. Also, despite the supposed boycott against Egypt, Business Week reports that "a surprisingly large number of Arab governments are continuing to put money into the Egyptian economy."

On his latest trip to Washington, Ezer Weizman, the Israeli defense minister, frankly summed up things this way: "I don't know what the final status of the West Bank is going to be . . . . There are certain problems in the world that don't have definite solutions . . . . I don't think we should discuss it now." That, apparently, is the way it is going to be.