When they stepped off the plane at Baltimore-Washington International Airport two months ago, Tashkent natives Bella and Alex Oster had already changed the lives of the 20 strangers waiting to greet them.

Weeks before the Soviet emigre's even knew there was a place called Howard County, members of Columbia's small Temple Beth Shalom had come to a collective decision. They would help rescue a Jewish family from the growing antisemitism in the Soviet Union, where "Jew" is being being scrawled on doors and Jewish workers are losing their jobs.

"This was the stuff they had talked about and marched for and demonstrated for," said Leonard Cohen, who helped lead the meeting of his fellow Beth Shalom members the night the decision was reached. "And now here, push was coming to shove. This was history, knocking at the door . . . .

"In one night," he said, "it went from an abstract thing -- should we do it, should we not do it -- to an end to debate."

The 129-family congregation founded 20 years ago has never had a permanent home of its own. In recent times, the synagogue's leaders have been struggling to amass a building fund.

But in just one emotion-packed evening late in April, Beth Shalom members pledged most of the $14,000 the Osters and their two children would need to survive the first year in this country.

"This is something that is very central to Jews," said Ronnie Sanderson, a social worker who has been assisting the new arrivals. "They don't want to feel that they let people sit in Russia and die. They don't want another Holocaust."

Beth Shalom's pledge has far surpassed money, furniture and a place to live. The congregation has become the Osters' extended family, driving them to stores and to English lessons at Howard County Community College, checking with them daily to see how they are doing.

In turn, Beth Shalom Rabbi Kenneth Cohen said, "the Osters have done far more for us than we have done for them. Their little apartment has become Grand Central Station. It has become a major gathering point for the congregation.

"Whenever I pop by there are always other members of the congregation there. They always have coffee and cake, and they always insist that we stay. So it's become the major salon of the Jewish community -- and in the real sense, because they're also very cultured people."

"It's one of the most cohesive things we've ever done," said Leonard Cohen, a Washington businessman. "People are proud of what they've done" for the Osters, he added.

"For both adults and children it's become a real political education," said Cohen's wife, Arlene Cohen, who was one of many Beth Shalom and Columbia Torah Minyan members who put in long hours preparing for the Osters' arrival. "Because it's become so real for us, we're really followers of the news now and we've definitely become involved. We've become real keen observers."

Elsewhere in Columbia, members of Temple Isaiah and the Columbia Jewish Congregation have made the same financial commitment to sponsor families from Odessa. The synagoges are part of a nationwide effort, called Operation Exodus, that began a year ago when it became clear that Soviet Jews would have to be resettled in increasing numbers.

A panic appeal went out from Jewish immigration agencies to congregations in small communities nationwide in April when it was learned that Italy, since the 1970s the holding country for Jewish Soviet refugees, was about to close its transient camps.

The agencies were seeking homes for about 8,000 Soviet Jews without relatives or other likely ponsors in this country. Large cities were already overburdened with many of the 40,000 Soviet emigre's being permitted into the United States in fiscal 1990.

Baltimore, with the seventh-largest concentration of new arrivals in the country, has taken in 1,149 refugees since last October, Sanderson said.

Since the 1970s, Columbia has been home to about 25 Soviet families who have immigrated with the help of refugee organizations. Close to 30 Soviet emigre's have relocated to Howard County, which has 7,000 to 10,000 Jewish residents, in the last 18 months, Sanderson said.

In mid-May, the Columbia congregations learned that their charges would be arriving in a week. By the time the Osters and the Odessa families arrived late and tired at BWI, two furnished apartments and a three-bedroom house were waiting for them.

"Reality is even nicer than we expected," Bella Oster, a 34-year-old music educator, said in her comfortable apartment in the Kings Contrivance village. "From the first moment here, we liked it." The Osters spoke haltingly in English, and in Russian through the translations of a new friend, Naum Levenson, who immigrated from the Soviet Union 11 years ago.

"I'm just sorry we couldn't home 10 years ago," said Alex Oster, 41, a radiologist who has written four books. After they were allowed to leave Tashkent, the Osters waited with their son and daughter in Italy for six months.

"We knew the name Baltimore," Alex Oster said, "but we couldn't find Columbia on the map. We found a lot of Columbias, but not in Maryland."

Life in Tashkent had become increasingly tense, the Osters said. As Soviet nationalism grew, their Russian and Uzbek neighbors were again speaking out openly against Jews, and the Oster children, Anna and Igor, were taunted by classmates. The Osters and their parents, all holders of advanced degrees, had lost their jobs.

"When the last Jew leaves the Soviet Union," Bella Oster said, "they won't have antisemitism."

The coming of the Osters and the other families to Columbia has "helped bring us back to our roots," Rabbi Cohen said.

Said Arlene Cohen: "We felt that this could have very readily been us. Our parents or grandparents made the trip."