The ambassador of Israel said his farewells last night, a Washington rite of passage as steeped in politics as it is in protocol.

"I reached the peak," said Ephraim Evron, 61, a small man of large reputation who spent 34 years -- virtually the entire life of modern Israel -- in his country's foreign service, "and one should retire when one is still ahead."

Last night there could be little doubt that he was very much ahead. More than 350 guests from the Cabinet, the Hill, the White House, the State Department, the media, the American Jewish community and just about every other aspect of official Washington life streamed into Israel's year-old, $5 million chancery at Van Ness Street and Reno Road.

"My friend and my buddy," said Egyptian Ambassador Ashraf Ghorbal, the first ambassador Evron met when he arrived here in December 1978, three months before Menachem Begin and Anwar Sadat signed the Israeli-Egyptian peace treaty at the White House.

"We've been like Siamese twins," said Evron of his and Ghorbal's frequent appearances together. "The public was intrigued by it."

Evron -- called Eppi by his friends -- never thought it quite so extraordinary considering, he said, how Israel and Egypt have been neighbors for 4,000 years.

"Our relationship goes a long time back, long before the Moslems," said Evron.

If Evron's most dramatic and satisfying moment was the signing of the peace treaty, the most anxious probably was the day before when, despite efforts of President Carter and then-Secretary of State Cyrus Vance, several important points remained in contention.

"Prime Minister Begin thought that maybe through direct contact with President Sadat he might be able to settle, so I called up Ambassador Ghorbal and arranged to meet Sunday afternoon."

It was the first time Evron had been inside the Egyptian Embassy and there was "a certain tension in the air, a coolness at first," he said, that seemed to disappear once Begin and Sadat set about working out their differences. The next day, the signing went ahead on schedule.

Though Evron, in an interview before last night's party, denied that he and Begin have been at odds -- "No," he said quietly at one point; "I'm not protesting anything," he said at another -- some guests saw him as an ambassador who had had his share of difficulties during his three years in Washington.

"He represented a country which did a lot the United States didn't like and it fell to Eppi to explain. At the same time he was not of Begin's party," said Gideon Samet, correspondent for Tel Aviv's Ha'aretz Daily. "There were shades of difference between the ambassador and his own government. He managed to juggle them with his own convictions."

Those familiar with Evron's successor, Moshe Arens, who is due here Feb. 12, called him a hard-liner who speaks "Beginese."

"Whatever advice Eppi gives him will be difficult for Arens to take," said Samet.

Still, in other parts of the starkly modern room where works by Israeli artists brightened the walls, people like I. L. Kenen, who founded the American-Israel Public Affairs Council, voiced wry optimism.

"Even years are election years and good for Israel. Odd years are bad. You'll see," Kenen told another guest, "this'll be a good year."

For his part, Evron only wished that people would understand Israel's "unique" situation.

"Israel is the only country in the world threatened by other countries with total extinction. We also have very little room for mistakes," said Evron.

That part hasn't really changed much from the early days, when he was an aide to Foreign Minister Moshe Sharett and later Prime Minister David Ben-Gurion. Between 1953, when he served in Washington for the first time, and his return in 1978, he had been ambassador to Sweden and Canada and eventually director general of the foreign ministry.

Diplomacy hasn't changed much either, in Evron's view: "I always think that in spite of what is now called instant diplomacy and the ease with which the leaders of government travel and meet each other, it has not diminished the role of an ambassador. If anything, it's made him more necessary, because without his input and legwork I doubt whether these meetings would be as productive."

Some things have changed. In mute testimony of that stands the very chancery whose foundation stone Evron laid in May 1979. Inside, the effect is that of a gallery; outside, beyond its iron fence, the effect is that of a fortress.

Evron said he never worried about his safety here or in any other country. "Somehow my generation has grown up with danger shadowing us all the time."

For almost three hours last night Evron welcomed people such as Attorney General William French Smith, FBI Director William Webster, White House counselor Edwin Meese III, AFL-CIO President Lane Kirkland, Deputy Secretary of State-designate Walter Stoessel, David Abshire of the Georgetown Center for Strategic and International Studies, Rep. Sidney Yates (D-Ill.), the American Jewish Committee's Hyman Bookbinder, the German and British ambassadors, journalist David Brinkley, former ambassador to Iran and CIA director Richard Helms, retired CIA official James Angleton, Joint Chiefs Chairman Gen. David Jones. And so on.

At Evron's side, petite and gracious, stood Rivka Evron.

"Everything I have done," Evron said, "is thanks to her."