Edgar Bronfman, head of the World Jewish Congress, said yesterday that Israel will have to make some "sacrifice and concessions" in order to achieve peace with its Arab neighbors in the Middle East.

Bronfman's remarks appeared to put some distance between the congress, which serves as an umbrella for Jewish organizations in 66 countries, and the official position of Prime Minister Menachem Begin's government. Bronfman spoke at the congress' biennial meeting here.

Saying that Israel's 3 million Jews cannot live securely in a region of 120 million Arabs without some political accommodation, Bronfman said, "It does us no good to fantasize about a peace that will come to the Middle East without sacrifice and concessions."

Bronfman did not specifically endorse President Reagan's Mideast peace initiative, which calls for Israel to surrender the West Bank and Gaza Strip to Jordanian control. The proposal has been rejected by Begin.

His comments, however, appeared to reinforce a trend among some American Jewish leaders and organizations that have called for Israel to show greater flexibility in seeking to end the Arab-Israeli conflict.

Moshe Arens, Israel's ambassador to the United States, took exception to some of Bronfman's remarks, asserting that American impatience over Israel's failure to withdraw its forces from Lebanon is misplaced. Arens said Israel will pull its troops out after it has satisfactory guarantees for the security of its northern borders, and he called for a "good dose of patience" while the Lebanon negotiations proceed. In a reference to news reports about the U.S. attitude, Arens criticized "unnamed officials" who have charged Israel with intransigence in the Lebanon talks. "Nobody wants peace more than Israel," he said.