Spiral of West Bank violence -- an eye for an eye for an eye . . . ?

It was over in minutes. Four masked men jumped from a car and fired a fusillade of machine-gun bullets into a crowd of Arab university students in Hebron, killing three and wounding 28.

Then they fled, leaving behind agonizing questions about whether the Israeli government's declared intent to resettle the ancient Jewish quarter in downtown Hebron in the midst of apprehensive Palestinians will set the stage for future rounds of violence between Arab and Jewish fanatics.

No one knows at this writing who committed the crime at the Islamic College in Hebron. It comes on the heels of the stabbing death of a Jewish seminary student, Aharon Gross, on July 7 by three Palestinian assailants in the center of Hebron. This incident was followed by the torching of the nearby Arab produce market by angry Jewish settlers seeking revenge.

One immediate question of observers here was whether the killing could be a further attempt to avenge the murder of Aharon Gross. Almost all Jewish settlers on the West Bank have permission to carry weapons. Arabs are forbidden to have weapons although some have managed to acquire them illegally.

Gen. Ori Orr, head of the Israeli Central Command, responding shortly after the murders to a question as to whether the investigation would proceed among both Jews and Arabs living in the area, said, ''Of course. We will try to find everyone, Jew or Arab.'' The Arab cities of Hebron and neighboring Halhul were immediately put under curfew. The curfew did not apply to the nearby Jewish suburb of Kiryat Arba.

Tuesday's killings and the Gross murder follow an intense campaign by Kiryat Arba settlers to win permission for the rebuilding of the abandoned ancient Jewish quarter in downtown Hebron. At first settlers squatted illegally in downtown buildings. In May 1980, the murder of six Kiryat Arba settlers by Palestinians in front of the first such building produced an initial government green light for the settlers' plan.

The Gross murder, while not yet eliciting official approval for the large-scale plan of the settlers, did draw a commitment from Defense Minister Moshe Arens. He said that Hebron's old Jewish quarter would be rebuilt ''just as we restored the Jewish quarter in the old city of Jerusalem that was destroyed in 1948.''

An injunction issued by the Israeli high court to stop settlers from tearing down buildings in the center of Hebron is now in doubt since the petition to the court was brought by acting Hebron Mayor Mustafa Natshe, who was dismissed by Israeli authorities following the Gross murder. The city's main bus station remains in Israeli Army hands and the local population fears it will be turned over to the settlers.

While government ministers solidly support the rebuilding of the Hebron Jewish quarter, the opposition Labor Party and the Israeli peace movement have expressed fears that this could provoke more violence on the part of hostile Palestinians and a fanatic fringe of Jewish settlers. About 2,000 members of the Israeli Peace Now movement demonstrated in Hebron last Saturday against the rebuilding of the quarter and for the return of the bus station.

Hebron, holy to both Jews and Muslims, is a city long familiar with fanaticism. Sprawling, conservative, and home to 70,000 Palestinians, it contains the traditional grave site of the biblical patriarchs Abraham, Isaac, and Jacob, over whose tombs stand a mosque and a post-1967 synagogue. The site has been the scene of ugly confrontations between Jewish and Muslim worshipers.

In 1929 the ancient Jewish quarter was emptied after a massacre by Arabs. In 1968, after Israel took over the West Bank during the 1967 Arab-Israeli war, a determined rabbi, Moshe Levinger, whose ascetic, bearded features reflect his fervent belief that Hebron is now meant to be a Jewish city, led a campaign of bringing in squatters and lobbying the government, which ultimately produced the Jewish suburb of Kiryat Arba above Hebron.

Today Kiryat Arba settlers complain that the Army does not protect them from attacks by Arabs. By this they mainly mean stone throwing by Arab youths that makes travel by settlers on the road dangerous and that could have the effect of discouraging new settlers. In response, settlers have undertaken numerous acts of vigilantism against Arabs, ranging from breaking Arabs' car and home windows to shooting, sometimes fatally.

While in a high percentage of cases Arabs are fined or jailed for stone throwing, it has proved more difficult to apprehend Jewish law breakers. The controversial Karp Committee report, a Justice Ministry study of unsolved cases of Jewish vigilantism which was shelved for a year and only brought to light when its author resigned from the committee this year, claimed police were hindered in such cases by their unclear jurisdiction over West Bank Jewish settlers and by political intervention from government members.

One advocate of vigilante violence is right-wing fringe leader Rabbi Meir Kahane, the American-born head of the violence-prone Kach Movement, which advocates expulsion of the Arabs from the West Bank.

Rabbi Kahane, who has a small but active following in Kiryat Arba, was infuriated by an Israeli court's sentencing, on the same day as the Gross murder , of teen-age Kach member Yisrael Fuchs to 39 months in jail for firing into an Arab car outside Hebron. Mr. Fuchs claimed the Arab had tried to run him down.