Menachem Begin's decision to resign as Israel's sixth prime minister ended a tumultuous personal era in the country's brief history, but it is not likely to change Israeli policy in the immediate future or lessen the difficulty of resolving the central conflict in the Middle East.

Whoever follows Begin as prime minister--most likely Foreign Minister Yitzhak Shamir--can be expected to be equally committed to Israel's retention of the occupied West Bank and to the absorption of the territory through the process of Jewish settlement. Changes in personality and negotiating style at the head of the Israeli government will not change this fundamental commitment, which the Reagan administration has described as "an obstacle to peace."

Nor will the formation of a new government alter the alignment of political forces established in the 1981 parliamentary elections, after which Begin's ruling Likud bloc, in coalition with smaller religious and right-wing parties, formed the current government.

The opposition Labor Alignment holds more seats in Israel's parliament, the Knesset, than the Likud. But the formation of governments in Israel has always been a matter of coalition building and most of the prospective small-party partners elected in 1981 are on the religious and nationalistic right--natural allies of the Likud.

Begin's successor is bound to be weaker and more vulnerable than Begin. He will be following in the footsteps of a national folk hero whose public career spanned the history of the country, and he will veer from the path established by the Begin government only at great peril.

As far as the West Bank and the future of its Palestinian Arab inhabitants are concerned, Begin deliberately has left him virtually no options.

There are now so many forces and interests behind the drive to retain the West Bank that perhaps only a political figure of the stature of Begin--who made Israel accept the evacuation of the Sinai as the price of peace with Egypt--could hope to reverse or even slow the process.

There may well be early elections before 1985 as a result of the Begin resignation, but it seems unlikely that they will radically alter the course of Israeli policy regarding the West Bank or the overall Arab-Israeli conflict.

The opposition Labor Party has shown greater strength in recent public opinion polls, but it remains divided and its leader, Shimon Peres, is a questionable political commodity.

But Begin's resignation does hand Labor an opportunity, one it has been waiting for in the full knowledge that so long as its opponents were led by the prime minister they were all but unbeatable. No one among the prospective new leaders of the Likud is thought to approach Begin in personal popularity or skill in arousing a following.

There is also a strong chance that in the post-Begin era his political allies will fall into the kind of bickering and infighting that has weakened and divided the Labor Party.

Begin's imminent formal resignation and the forced departure of Ariel Sharon from his post as defense minister earlier this year mean that in little more than a year after Israel's invasion of Lebanon the two chief architects of the war have retired to the sidelines of power. Sharon is still a force to be reckoned with, and Begin's resignation will undoubtedly trigger a new effort by the former defense minister to regain a position of leadership.

But Sharon has many enemies within his political party, Herut, and is identified not only with the military victory of last summer but with the disappointments and disillusionments that followed it.

While Sharon and others are maneuvering, Israel is likely to be consumed by internal politics that could lead to a Knesset vote for early elections. At the same time, the American presidential election campaign will be getting into full swing. Together, the domestic preoccupations of the two countries would appear to be a recipe for diplomatic paralysis in the Middle East, perhaps for months to come.

The events of the past 48 hours--Begin's announcement of his intention to resign, the frantic efforts to get him to change his mind, his final decision today which still fell short of a formal resignation--may be just a preview of what lies in store for Israel. Yet for all the government turmoil, the drama has taken place in an atmosphere of public calm.

Demonstrators chanting their devotion turned out at Begin's office and his home each day to urge him to stay on, but they were few in number. There was no general public clamoring for Menachem Begin to continue to lead Israel.

It was almost as if the Israeli public, seeing their sad and weakened prime minister, instinctively knew and accepted the fact that the Begin era was at its end, even as his desperate political colleagues fought to the last against the prospect of facing the future without him.