"We win all the arguments, but we lose all the votes," Abba Eban, Israel's former foreign minister who is now in opposition, remarked to me the other day as we chatted in the Knesset.

The complaint was overheard by Prime Minister Menachem Begin's chief assistant, Yehiel Kadishai. "Long live the majority," he cackled.

That exchange expresses exactly political conditions in Israel. Despite many signs of weakness, Begin is firmly in control of his parliamentary majority, and hence of his government and the country.

Forces for fragmentation, to be sure, abound in the Begin regime. His parliamentary majority (with 78 ou of 120 seats in the Knesset) comprises six different parties, which are at odds on many issues. Ford of the parties (the Liberals, the Democratic Movement for Change and two religious factions) do not even share the enthusiasm of Begin and his own Herut Party for Jewish settlements in occupied territory west of the Jordan River.

Tparty rifts inside the majority are complemented by personal rivalries. Two shining military figures - Foreign Minister Moshe Dayan and Defense Minister East Weizman - have far more popular appeal than Begin, and entertain notions of sitting in his seat as prime minister. They are both less hawkish, at least in tone, than he is on settlements and the West Bank.

The official opposition (with 42 votes, of which the Labor Pary has 32) runs athwart the government at it chief point of division: the settlements and the West Bank. For the first time in Israeli history, the political battle line is drawn around the issue of occupied territory with a considerable faction of the Knesset (56 of the 120 members, by one authoritative count) favoring a more dovish line than the government.

Moreover, dovish opposition finds resonance in a peace movement. Some 30,000 Israelis, led by decorated war veterans, met in Tel Aviv a week ago Saturday to demonstrate for "Peace Now." Their chief message was that the Begin government should make territorial concessions rather than miss the chance for a settlement with Egypt.

But Israel is the last refuge of organized party politics. So when you put all these discordant elements together and shake them up, what comes out is not an explosive mixture but more of the Begin government. The dissident parties in the majority, many of whom have always run under Begin's standard at the polls, preferred to work from within rather than break openly and precipitate and election.

The two heroes - Dayan and Weitzman - are so much at odds personally that each tends to cancel the moves of the other. Neither has a party following, and each can be - and has been - politically isolated.

The labor opposition, as its leader Shimon Peres, told me, prefers that peace be made by hawks rather than doves. "The government can bring a settlement more quickly and with less internal dissension than we can," Peres said. "We're in no hurry to come back to office."

Even the peace movement is problematical. "It could be the beginning of a ground swell." Liova Eliav, a leading dove who helped to organize the Tel Aviv demonstration, told me. "But the demonstrators are in the lead group tha tis not in touch with the blue-collar workers. The movement could easily fizzle."

In these conditions, Begin holds the country firmly in his grasp. A policy of trying to force him from power - which some of those around President Carter undoubtedly favor - is certain to backfire. A policy of driving wedges between the prime minister and the other government figures - which President Anwar Sadat of Egypt is now following - canot succeed.

For better or worse, accordingly, the current peace efforts have to be worked through a government dominated by Begin. it may not be all for the worse. When I interviewed the prime minister the other day with David Greenway of this newspaper, it seemed clear to me that he was over the period of bitter feeling and remorse occasioned by his recent trip to Washington. He seemed in good spirits, talked in moderate terms and looked not backwards but toward the future.