Up and down the rolling hills of suburban Potomac they walk, pushing a baby carriage past a golf course and into a ditch on a narrow, curving road, wending their way across a schoolyard and through lush subdivisions where lawnmowers hum. It is Saturday when Jews gather for prayers at the synagogue, and Adie and Niel Roth, an Orthodox couple, are walking there - all 2 1/2 miles of it.

Their gait is swift as they walk from their brick-and-frame home in the Eldwick subdivision to Beth Shaolom Congregation's suburban chapel at Seven Locks and Post Oak Roads. Chave, 14 months, is tucked into a babby carriage with cookies, a bottle and diapers. When he tires, Adam, 4, his curly blond hair topped with an embroidered yarmulke, hops in for a ride.

They pass all kinds of activities forbidden Orthodox Jews on the sabbath. They walk because Jewish law prohibits driving or riding on that day. Some autos swerve around them as they walk rapidly on busy roads without sidewalks. A youthful skateboard artist weaves in and out of their path and a biker speeds alongside. Golfers, housepainters, carwashers and horseback riders come in and out of view.

"The whole week revolves around the sabbath," explained Roth, 35, mathematical and statistical consultant. His wife, Adie, 34, covers her black hair with a kerchief for the trip.

For this Jewish family, Saturday is a sanctuary in time. On this day, the sabbath they set aside many modern conveniences for the ancient command of their faith. On the sabbath, Judism teaches the natural harmony between human beings and nature should not be interrupted.

They don't answer the telephone, spend money or do extensive cooking on the sabbath. Necessary lights and the oven and burners on the stove are turned on the night before the sabbath so they won't have to flick switches. Mrs. Roth keeps two sets of dishes to separate meat and milk products and another two for Passover, as the religious law commands.

"Traditionally our families have always observed these laws," she said.

But life in suburban Washington is considerably different from the way the Roths grew up. Here, in the suburbs where friends and kin live miles apart, where neighborhoods are ethnically mixed and where the temple, the Hebrew school and other religious institutions are frequently a 30-minute drive from home, religious observance comes less easily than in Roth's former Jewish community.

There, on the Lower East Side of New York, he recalled, "everyone else was like you." As a youngster, though born in this country, he spoke only Yiddish until he entered first grade, and he attended synagogue daily for prayers.

"You'd go out on Saturdays and just thousands of Orthodox people were sitting around to talk to," said Roth. Many of his New York neighbors were Hassidic Jews the men wearing black suits and full beards; the women, wigs to cover their shaved heads, and the boys, long coiling sideburns.

Roth went on to earn a doctorate in theoretical mathematics and moved to Washington. It was then he and Adie began developing their own style of religious practice, blending a modern way of life with traditional beliefs.

"In my entirely life," said Roth. "I have never eaten anything that wasn't kosher . . . After a certain hour, I will not fly on Fridays (when the sabbath begins an hour before sundown). I've been stranded in cities at tremendous expense, but I've learned to plan in advance. If I'm driving and I get stuck in a traffic at a certain hour on Fridays I'd probably leave my car and walk home."

"Some things are so ingrained, but with everyone it's different. Some Jews keep kosher homes and when they go out they'll do anything. Among certain people kosher food is important. Among others, it isn't, but going to the synagogue is. Everyone cuts their line in a different place," he said.

At home, Adam keeps a charity box, learning at an early age that he should give money to all sorts of causes, including Israel. The family prays at meals and Adam - and soon Chave - hears stories almost daily about Jewish history and tradition.

"We grew up in a more Orthodox environment than our children will," said Roth, "but we hope they can see the tremendous satisfactions of this way of life."

So, they choose to walk to synagogue on Saturdays while some Orthodox Jews now drive. Yet the Roths push a baby carriage, which some orthodox will not do.

The excursion itself is to them exhilarating, calling to mind the satisfactions of warm family ties and close friends. Often they hike with their neighbors, the Arkings, who moved to the same cul-de-sac with them. "We could never have come here alone," said Roth.

Al Arking, a physicist at Goddard Space Flight Center, and Roth paced the distance to the temple before buying their homes. Three-and-a-half miles "is about the limit," Roth conceded.

Sometimes the heat is hard to bear, and when they return home, the seven miles behind them, the Roths sink into their thick-cusioned sofa and revel in the air conditioning. At least once a year, for Simchat Torah celebration in the fall, they make the cross-lots journey after dark. And during the High Holidays, the most sacred Jewish festival, they spend the 10-day period in the homes of friends or relatives in Silver Spring or New [TEXT OMITTED FROM SOURCE]

Arking devotes his weekly synagogue trip to tell his young sons stories, making up "subtle moral" themes as he goes along. The men turn often to discussions of politics, science and finance. "Invariably when we're coming home," said Roth with a laugh, "we talk about where we've going to buy our next homes - closer to the synagogue.

"It's a day different from the rest of the week," said Adie Roth. "We do things as a family and as an extended family. We know we're not going to be involved with everyday kinds of things.It's a feeling of relief, a day when we can relax and be just for ourselves."

Now and then, Roth admits he feels a twinge when the journey takes them past youth league soccer games, which he acknowledges his son cannot join, or when he observes the look on Adam's face as his young friends take off for the zoo on the Jewish sabbath.

His children cause his deepest reflection. "With the impositions Adie and I have faced, we could have walked away from our faith long ago if we'd wanted to. But where is Adam going to stand if we continue living in a place like we are now, and don't make a super-valiant effort for our religion? I have deep reservations whether he will be as religious a Jew as I am.

"Who are his friends going to be?" Roth mused. "Where is he going to find an Orthodox girl, someone who will conform to his way? I feel that if we teach him the positive things about his religion, let him ask questions, get him involved - that counts for an awful lot."