For the last four years, Rabbi Ariann Weitzman’s synagogue in suburban Montclair, New Jersey has kept its doors locked “at all times.”

The congregation at Bnai Keshet has a standing security committee. Worshippers must plug in a code to enter the building, or hope that someone who recognizes them sees them hovering by the door.

Some congregants, at first uneasy with the new security measures, became accustomed to the presence of nearby police. Officers were around the synagogue “often,” Weitzman said. “All the time,” she clarified.

A security guard who had once been an unfamiliar face during religious services now served as a grim reminder of the reality Jews in the U.S. have to navigate, as they worship at synagogues and shop at kosher markets.

“They do a little bit to make these people feel safer,” Weitzman said, “but there’s really no security measure that mitigates the sense of existential threat, you know?”

One day before Shabbat, the FBI warned of a “broad threat to synagogues” in New Jersey. On Friday morning, authorities announced they had “identified the source of the threat.”

The suspect “no longer poses a danger to the community,” the FBI’s Newark outpost declared shortly after 11 a.m., after a frenzy of phone calls to congregants and coordination with law enforcement and private security details had ensued within the state’s Jewish communities.

Synagogues in New Jersey and around the country have ramped up security measures in a pattern seen by American Jews as a response to the rising tides of extremist hatred. Antisemitic incidents in 2021 were up 34% from those reported in 2020 according to the Anti-Defamation League — the 2,717 incidents reported last year set a record since the group began keeping track in 1979.

“The way that a society treats their Jews, it's like the canary in a coal mine,” said Rabbi Leana Moritt of Temple Beth-El in Jersey City. “It’s an indicator of the health of a society.”

Rabbi Douglas Sagal, who leads the Congregation B’Nai Israel in Rumson, New Jersey, said the threats represent an existential threat — not only to Jews, but to American society.

“As antisemitism increases, it’s indicative of the sickness of society itself,” Sagal said. “Quite frankly, I am concerned for the future of our nation.”

Though federal authorities said they had contained the immediate threat to New Jersey synagogues, it did little to assuage long-standing fears. Jewish communities and their allies note antisemitism has become more visible in recent years: the white supremacist rally in Charlottesville, Virginia, in 2017; the shooting of a synagogue in Pittsburgh in 2018; the mass shooting at a kosher market in Jersey City in 2019.

Still, many Jewish faith leaders interviewed by Gothamist on Friday emphasized the need to stay resolute in the face of terror.

“I think one of the things we’ve learned is that there’s no benefit to submitting to antisemitism and threats,” Sagal said. “That the only appropriate response is to stand fast.”

Jewish leaders said they planned ahead of Shabbat services with the same brand of vigilance they had grown accustomed to in recent years — perhaps with sharper notes in the face of the FBI’s recent warning.

“This course wasn’t offered in seminary,” said Moritt. “This is not why we do the work that we do. Obviously, it’s to support and protect our people, but it distracts us from the work we do best, but we do what we have to do.”

Jewish religious leaders said many members had been “determined” to maintain their usual course for Friday evening — an act of defiance against threats Jews have known for centuries.

“I come to work in a synagogue every single day. I want to keep doing that for the rest of my career,” said Weitzman, before the FBI announced that the threat's source had been identified. “There’s nothing more important in my life than living proudly and openly as a Jew.”

Weitzman said she embraced safety measures that allowed her and her children to do so.

“At the same time, I experience all of these threats as a spiritual call to arms,” Weitzman said. “I just have to be louder about being Jewish in public.”

Correction: A previous version of this story misstated the location of Temple Beth-El. It is in Jersey City.