Not long into his first term, the president made an epochal pledge to the American Jewish community, affirming the Constitution's vision of a nation of diverse faiths, committed to equality and acceptance. His government, he assured, would give "to bigotry no sanction, to persecution no assistance," and require only that "they who live under its protection" should comport themselves as "good citizens."

The year was 1790, and the commander-in-chief was George Washington, whose letter guaranteeing religious freedom is considered to be among the most important documents -- some say the most important -- in American Jewish history.

More than two centuries later, his 340-word missive will soar again, as a cantata to debut Friday at Reform Congregation Keneseth Israel in Elkins Park.

New York composer Jonathan Comisar had been commissioned to craft the work to commemorate the congregation's 170th anniversary. But in the six months since he and Rabbi Lance Sussman of Keneseth Israel selected the subject for the musical narrative, a troubling wave of anti-Semitism has manifested itself in desecrated cemeteries,  bomb threats, and shattered synagogue windows.

Suddenly, the words of Washington's "Letter to the Hebrew Congregation of Newport, Rhode Island" took on new urgency, reflecting ideals as "resonant and powerful" as ever, Comisar said. A celebratory composition became a call to action.

The 12-minute cantata, "To Bigotry No Sanction: An American Jewish Cantata,"  is a sweeping combination of Hebrew, hymn, and colonial music.  "We wanted a serious piece of music. We wanted a statement," said Cantor Amy Levy of Keneseth Israel. "Music is a vessel of the Jewish experience, a voice of hope and comfort, especially in times when we've been oppressed or in need of healing."

The letter "didn't sweep away prejudice," said Sussman, who is also a historian. Washington singled out  "the children of the stock of Abraham," hoping that they – and their fellow Americans --  would  be able to "sit in the safety under his own vine and fig tree and there shall be none to make him afraid."

On long-term loan from the Morris Morgenstern Foundation, the letter is on exhibit at the National Museum of American Jewish History in Philadelphia through Sunday. It is "probably the most significant document in the history of Jews in the U.S. and also one of the most important documents in American history," chief curator Josh Perelman said.

Washington wrote it after a visit in August 1790 to Newport to thank its citizens for voting to ratify the Constitution, which the state approved that year.  About 200 of the young nation's 2,500 Jews lived in Newport.

Moses Seixas, sexton of Congregation Yeshuat Israel in Newport (now Touro Synagogue), read an address to Washington during a meeting with residents.

"Deprived as we heretofore have been of the invaluable rights of free Citizens," Seixas said, "we now with a deep sense of gratitude to the Almighty disposer of all events behold a Government, erected by the Majesty of the People -- a Government, which to bigotry gives no sanction, to persecution no assistance."

When Washington returned to New York City, he penned a letter in response -- borrowing a quote from the sexton that would become an enduring phrase. Washington wrote that the "Government of the United States, which gives to bigotry no sanction, to persecution no assistance, requires only that they who live under its protection should demean themselves as good citizens."

He also appropriated the Biblical words of the prophet Micah, stating that every American should be free to sit "in the safety under his own vine and fig tree and there shall be none to make him afraid."

The letter was signed, "G. Washington."

Comisar, also an ordained cantor and musical theater composer, sought to capture the enduring relevance of the document. He acknowledges that the Founding Fathers weren't perfect.  They "had blind spots when it came to the rights of everyone," Comisar said. "They didn't include African Americans and women," and Washington owned slaves.  Yet the seeds of an American ethos in which people would be accepted and protected were "inherent from the beginning."

His cantata starts with a bellow from a French horn, meant to invoke the solemnity of Washington's words, but the composition's first lyrics are Micah's reflections on freedom and safety, spoken in Hebrew. The piece will be performed by a 30-voice adult choir, a small children's chorus, and six musicians.

"We have a history of persecution and wandering from place to place," Comisar said, "America was a refuge and a harbor for our religious freedom, but those things hang in the balance right now."

“To Bigotry No Sanction: An American Jewish Cantata” will be performed at 7 p.m. Friday at Reform Congregation Keneseth Israel, 8339 Old York Rd., Elkins Park. Admission is free. For information, call 215-887-8700.