Ben-Gurion’s matter-of-fact voice from the grave resonates hauntingly, with its mix of pragmatism and philosophical prescriptions bordering on the prophetic. He described the prophet Jeremiah as one of the greatest because, he said, “I have the feeling that what he was saying is true.”

“He understood politics more than the kings,” Ben-Gurion said. “But he was unpopular.”

Mr. Mozer and Mr. Shilon pointed to the former prime minister’s pronouncements at the time that in return for a true peace, he would give up the territories that Israel conquered in the Arab-Israeli War in 1967, except for the Golan Heights, Jerusalem and the West Bank city of Hebron. He saw no contradiction in believing that Israel had the right to all the land, but could also concede some of it.

“He thought that the most important thing was to live in the Middle East in peace with our neighbors,” Mr. Shilon said. “He said that Israel can win a lot of wars and the Arabs can lose a lot of wars, but that Israel would not be able to stand one defeat; that one lost war would be the end of Israel.” Mr. Shilon added, “The problem with Ben-Gurion was that people stopped listening to him.”

Mr. Mozer and Yael Perlov, the editor and co-producer of the documentary, uncovered the lost interview almost by chance, in the Steven Spielberg Jewish Film Archive in Jerusalem. There, while working to restore an old and unsuccessful feature film about Ben-Gurion by Ms. Perlov’s late father, David Perlov, they tripped across the silent film reels. It took six months to find the soundtrack, which they did in the Ben-Gurion Archives in the Negev.

The interview had actually been conducted as background research for the Perlov film. The former prime minister had chosen the interviewer, Clinton Bailey, who was then a recent immigrant from the United States. Mr. Bailey had been befriended by the Ben-Gurions after Paula invited him in for tea one day when he was wandering near their home in Tel Aviv.