"Do you think my country is afraid of peace?" an Israeli journalist asked as we waited to hear Prime Minister Menahem Begin tell the Knesset he was accepting President Anwar Sadat's invitation to begin negotiations in Cairo. "I don't know," I said. "Maybe I'll find out now."

I didn't find out. But what I saw and heard in the Knesset was not wholly reassuring.

Begin dominated the proceedings from beginning to end. He spoke twice from the rostrum, showing himself to be an accomplished parliamentarian, good at the cut and thrust of debate, skilled at drowning controversy in tedium and not above applying a little schmalz to drive home a winning argument.

He was accused once of violating the Sabbath in dealing with Egypt. He protested mightily by reading a passage on the Sabbath from the Bible. As he read, to prove his piety, he put a skull cap on his head.

Between speeches he retired to the Knesset cafeteria. He ordered a cold chicken and carved it with force and a certain elegance. As he ate, Cabinet ministers, knesset members, secretaries and journalists swarmed about him.

At one point he beckoned me to sit down, recalling with easy flattery a visit I had made to his home a couple of years ago. Contrasting the then and the now, he spoke of his warm personal rapport with other leaders: President Carter, Nicolae Ceaucescu of Rumania, Sadat and Prime Minister James Calaghan of Britain.

"I'm going to remind the Europeans," he said, "of the Holocaust and the rivers of Jewish blood. I'll talk even to the Dutch. They helped protect the Jews. But I will tell them we don't want our daughters to leave behind books like "The Diary of Anne Frank."

He anticipated a question I was going to ask about what response Israel could make commensurate with Sadat's visit to Jersualem. "Journalists think I should go to Cairo," he said. "But that isn't what Sadat wants. In fact he asked me to visit Ismailia on the Suez Canal. I told him I did not need a halfway house. When the right time comes, I'll go to Cairo."

That bravura performance was marred for me by three comments Begin made in the Knesset debate. "Let us not compete," he said at one point, "in trying to prove to each other who is more peace-loving." I took that as a kind of put-down of the statements advocating a more flexible Israeli position made by Deputy Prime Minister Yigal Yadin, Foreign Minister Moshe Dayan and Defense Minister Ezer Weitzman.

At another point he questioned a statement by opposition leader Shimon Peres respecting the territory west of the Jordan River that Israel seized from Jordan in 1967 and still occupies. Peres indicated his Labor Party would support territorial concessions on the West Bank or any other kind of concession. Begin challenged that offer as though it reflected indecision.

Finally, in a long harangue, Begin insisted the word "Palestine" did not exist in Hebrew. He said it was just "jargon." The word 'jargon' is also 'jargon,'" someone than said. "But it exists."

Behind these exchanges lies an agonizing choice. In negotiating with Sadat, Begin can go for a settlement that embraces Egypt, Jordan and at least some moderate Palestinian Arabs from the West Bank of the Jordan. Such an accord would probably have the support of Saudi Arabia and would encompass the great preponderance of economic and military strength in the Middle East.

To get such an accord, however, Begin would have to make concessions on the West Bank, which Sadat could then use to bring King Hussein of Jordan and the moderate Palestinians into the deal. But Begin previously ruled out concessions in the West Bank, which he has called "sacred" to Israel.

Another possibility is to go for a bilateral deal with Egypt. That would practically end the danger of war, without requiring concessions on the West Bank. But a separate peace might discredit Sadat with the other Arabs to the point where it would fall through.

I do not think Begin has yet made his choice. I think his faith, which is powerful, pushes him toward a separate peace, while his sense of history, which is also strong, works for the larger objective. So I think it behooves all of Israel's friends, including, especially, the United States, to interest the prime minister in the larger objective. For if Israel does not at least try to get the bigger, pro-Western deal, it will be hard to believe she is not afraid of peace.