Rabbi Sanford Rosen hightailed it down the street, sweating under the hot, Alabama sun — and also because a pack of chain-wielding, white supremacist thugs were hot on his heels.

Thankfully, a couple of passing soldiers in a jeep asked the rabbi if he could use a lift. Boy could he ever.

Rosen, the founding rabbi of Peninsula Temple Beth El, made his trip to the Deep South with the overwhelming blessing of his congregation — which celebrates its 50th anniversary in March. While most of the temple's forays into social activism didn't put its rabbis' lives on the line, this has always been a congregation with a conscience.

In the years since Rosen marched with Martin Luther King from Selma to Montgomery in 1965, the San Mateo Reform congregation has reached out to the homeless and disadvantaged, extended aid to Israel and even voted to boycott grapes along with Cesar Chavez. "I think we lost a few members over that because we had people in the fruit business," says Rosen, now rabbi emeritus, with a chuckle.

And through it all, say congregants and clergy, the temple has maintained a sense of camaraderie extraordinarily tight for a synagogue of more than 700 families.

"When I first arrived here, it was described as a chavurah with thousands of people," said Rabbi Alan Berg, the congregation's spiritual leader for the past 10 years. "There seems to be a really strong connection people have."

Peninsula Temple Beth El has come a long way since groups of parents began organizing a religious school in 1950. A year later, they began to think about forming a congregation at the behest of a young Rosen in a living-room discussion at the home of Jerry and Esther Moskovitz.

Rosen, who had managed to start up a congregation in Bakersfield with 120 families, made his Peninsula pitch at the behest of Rabbis Alvin Fine of Congregation Emanu-El and Morris Goldstein of Sherith Israel. The two San Francisco rabbis felt it would be more convenient for Reform Jews on the Peninsula — and, frankly, for them — if congregants' needs could be met without a long drive to and from San Francisco.

Rosen's message was taken to heart by the Peninsula Jews, and so was he. Rosen was hired to be the congregation's first rabbi, and incorporation papers were filed. Riding the Peninsula's swelling population wave, the congregation boasted hundreds of families within a few years and, by the late 1950s, had more than 600 children in its religious school alone.

In 1955, a significant number of Beth El's roughly 450 families left to form Burlingame's Peninsula Temple Sholom. Years later, former Beth El congregants also helped to form Congregation Beth Am in Los Altos Hills.

While the split bothered a lot of congregants at the time, according to Beth El historian Joan Abrams, nonetheless Rosen looks back at those days with something of a sense of pride.

The Peninsula had proven fertile enough for not one but three Reform synagogues. Rabbis Fine and Goldstein had been right when they told Rosen the Peninsula could support a congregation of its own.

By 1957, Peninsula Temple Beth El had built its current home on Alameda de las Pulgas. Because the carpeting and plumbing may still have dated from the Eisenhower era, congregants today are pleased the temple's 50th anniversary celebration on March 2 also marks the official unveiling of the completely revamped sanctuary interior.

In addition to installing air-conditioning and sprinkler systems, the sanctuary is now completely accessible to the disabled. A large Hebrew calendar crafted of glass and Jerusalem stone serves as a partition between the social hall and sanctuary. And in the most extensive change, all-new pews have been installed in a rounded, amphitheater-like pattern.

The project required four years of planning and fund-raising, and cost roughly $2.4 million.

"Our leadership, both lay and clerical, and our programs, everything is top-notch," said Martin Lowenstein, chairman of the sanctuary renovation campaign and a congregant since the early 1970s.

"Now the building is up to the same caliber as everything else that goes on here."