To the soft notes of an acoustic guitar, the congregation of Temple Beth Ami in Rockville last night sang this Sabbath hymn: "The entire world is a narrow bridge. But the main thing is not to fear."

But there was fear, etched on the faces of worshipers, each of whom had to pass through doors bearing a sign reminding them that the doors were locked for security reasons. Those entering had to press a doorbell. A little girl told how her elementary school was briefly emptied by a bomb threat. Young families who hadn't been to synagogue in a while suddenly felt a need to be close to other Jewish people.

"I had signed up for Shabbat dinner before all of this happened," said Caryl Raport, of Rockville. "I felt that it was even more urgent to be a part of something like this in lieu of what might happen."

Twenty-four hours after several Iraqi Scud missiles landed in populated areas of Israel and after a day of false alarms, but before a second Iraqi missile attack on Israel, the congregation struggled to put emotions into words in a somber service.

"My notes this evening are a jumble because that is how I feel," said Rabbi Jack Luxemburg. "Like everybody else, I've ridden this roller coaster of emotion. I have to worry about Israel. Not only that it has been hit by missiles and has shown its vulnerability, but also about the burden that she might have to carry.

"In my heart of hearts, I believe that to refrain at this point is good," Luxemburg told the congregation. "I can't imagine how I would feel if Israel is attacked with nonconventional weapons. Auschwitz still runs in our veins. People do not understand completely the specter of gas to Jews."

Many at the service were weary from staying up late for two days straight, watching television news or waiting for telephone calls from family and friends in Israel.

"We are almost living in two time zones," Anita Finkleman said during a discussion held at the service. "Tonight, we are almost counting the hours until it's sun-up over there."

Ronald H. Wohl said he was concerned that stress was starting to show in many in the Jewish community. "I have fears about our own sensibilities. We are sitting up every night. I have a great concern for those of us who are here, how we treat each other because of the stress."

For parents like Jim and Linda Siegel, worries were largely for their children. For the first time, Linda Siegel said, she had to go through a front door instead of a side door to drop her son at nursery school so that officials could verify the identity of each person.

Elizabeth Raport, 8, learned firsthand about the war yesterday when a bomb threat emptied Beall Elementary School in Rockville. "Everything is going crazy," she said.