Bruce Laingen remembered exactly where he and Algerian Ambassador Redha Malek first met--in the aisle of an Algerian airplane as it sat on the tarmac in Iran waiting to take off for Algiers.

That was Jan. 20, 1981, and Malek was one of the Algerian diplomats who had been acceptable to Iran in working work out details of its release of the 52 American hostages, professionals from a non-aligned country Laingen called "crucial in the process that saw us released--if they had not been there, someone would have had to create the Algerians."

Malek and his wife stood in the doorway to the flagstone terrace where Perle Mesta once held court as chatelaine of The Elms, and later where Lyndon Johnson, as vice president, lived in full Texas bravado. The Maleks, who leave at the end of July to preside over Algeria's embassy in London, were hosting a farewell reception at their residence last night for past and present government officials, social Washington and yet a third category of guests that included celebrities like Laingen, fellow former hostage John Graves and Judge John Sirica of Watergate fame.

"I'll never be able to thank you enough for all you did for us," Laingen told Malek, who looked pleased but uncomfortable. "A very modest, self-effacing man," Laingen said later.

His description proved to be only too accurate as others drifted in and out of the balmy summer evening to heap praise upon the Algerian. Soviet Ambassador Anatoliy Dobrynin's presentation of a farewell plaque brought a flustered thank you from the Algerian. He characteristically looked the other way when FBI Director William Webster told him he'd be missed.

Outside, diplomacy was at its Washington best as Arab ambassadors addressed themselves to events in Lebanon and the fall-out in Foggy Bottom.

"Everybody is concerned now about the security of other Arab parties," said Jordanian Ambassador Abdul Hadi Majali. "If the United States can't do anything to stop the invasion of other countries, the other countries that rely on support of the United States will lose that confidence . . . By not stopping them, the Israelis got the message that Alexander Haig wouldn't do anything."

The United Arab League's Clovis Maksoud expressed certainty that as secretary of state, George Shultz "would be less permissive and hopefully more sensitive. We do not expect reversal of American policy because there are certain constants, but I'm sure Shultz will be more open-minded to Arab perceptions."

Haig, Maksoud continued, was perceived by "all the Arabs as having licensed not only the invasion but the genocidal dimensions of it . . . The American public is beginning to be aware of the monster--Israel--they have unwittingly unleased. Many people who have been perpetually pro-Israel are beginning to realize that Israel is a burden on the American conscience. And many Jews, perhaps a silenced majority of Jews, are entertaining serious questions about Israeli Defense Minister Ariel Sharon's attempts to make a coup d'etat inside Israel through Lebanon."

Maksoud's wife, Hala, executive director of the newly formed Arab Women's Council, was keeping her nightly silent vigil with others in the group out in front of the White House to emphasize the human costs of the war in Lebanon. The council's president, Nouha Alhegelan, at the party with her husband, the Saudi Arabian ambassador, said she and others in the group were scheduled to discuss their work on CBS television's "Morning News" today.