One date, more than any other, has been a touchstone for Rabbi Arthur Waskow.

It was an April 4 when the Rev. Dr. Martin Luther King Jr. famously condemned the Vietnam War in a speech in New York in 1967.

It was April 4 one year later when King was fatally shot on a Memphis motel balcony.

It was April 4 a year after that when 800 Jews and Christians crowded into the basement of a Baptist church in Washington to mark the beginning of Passover with Waskow's groundbreaking interfaith  Freedom Seder, inspired by the civil rights movement.

Now, with the 50th anniversary of King's assassination fast upon a divided nation, the activist rabbi from Mount Airy has again updated the Haggadah — the text recited during the Seder — this time fusing the ancient story of the Jews' flight from bondage in Egypt with a story of America in turmoil.

The MLK+50 Interfaith Freedom Seder is Waskow's reconsideration of the traditional observance of Passover, the eight-day Jewish holiday that begins at sundown Friday. This year, it coincides with Good Friday and Easter, the holiest days on the Christian calendar, as well as half-century observances of  King's death.

Guests Listen as Rabbi Arthur Waskow speaks during the at the National Museum of American Jewish History’s annual celebration of the Freedom Seder.
TOM GRALISH / Staff Photographer
Guests Listen as Rabbi Arthur Waskow speaks during the at the National Museum of American Jewish History’s annual celebration of the Freedom Seder.

Waskow's ceremony reflects a nation as turbulent today as it was in the 1960s. It includes calls for nonviolence from King and Mahatma Gandhi. It touches on police shootings and the protests that explode in their wake. It encompasses the Parkland, Fla., massacre, and the students who organized last weekend's "March for Our Lives." It quotes the actress Viola Davis, speaking about the #MeToo movement at the Women's March in Los Angeles.

"Pharaoh is in the White House," said Waskow, 84, during an appearance Monday at the National Museum of American Jewish History's annual celebration of the Freedom Seder.

A guest table at the National Museum of American Jewish History in Philadelphia, with a coloring-book guide to the Seder plate that includes symbolic items representing Passover themes.
TOM GRALISH / Staff Photographer
A guest table at the National Museum of American Jewish History in Philadelphia, with a coloring-book guide to the Seder plate that includes symbolic items representing Passover themes.

He went on to accuse President Trump of using "racism, hatred of foreigners, of Muslims, and contempt for women, [and putting] it all together in a witch's brew that enabled him to get elected. We are in a crisis as deep as 1968."

In the years leading up to his original Freedom Seder, Waskow was a resident fellow with the Institute for Policy Studies, a liberal think tank in Washington. After King's murder, riots erupted, a curfew was instituted, and nearly 14,000 federal troops were called  in to occupy the district. Waskow worked with other activists to funnel food and medical and legal aid to the black community.

When he walked by a Jeep with a machine gun pointed at the street, he said, he realized the connection between slavery in ancient Egypt and subjugation in 1960s America. Disconnected from his faith, he was inspired to explore Judaism and write the Freedom Seder, which was published by Ramparts, then a leading liberal magazine.

The first Freedom Seder was held on April 4, 1969, at Lincoln Temple United Church of Christ in Washington.

Rabbi Arthur Waskow (center) with the Rev. Channing Phillips (left) and TV director Topper Carew (right) at the first Freedom Seder.
Rabbi Arthur Waskow
Rabbi Arthur Waskow (center) with the Rev. Channing Phillips (left) and TV director Topper Carew (right) at the first Freedom Seder.

TV director Topper Carew, then also a fellow at the institute, sat beside Waskow at the seder, but had no idea he was participating in something historic.

"I didn't know anything about a Freedom Seder," said Carew, now 74. "But I have since learned more about the parallel between the historic struggle of the Jewish people and the struggle of black people vis-a-vis the civil rights movement, and that's why it continues to be significant."

For the first Freedom Seder, Waskow took the portion of the Haggadah that includes a debate about the plagues God inflicted on the Egyptians and replaced it with quotes by slave-rebellion leader Nat Turner on resisting bondage, poet Henry David Thoreau on abolitionist John Brown, and King on nonviolence.

Not everyone loved the reimagination of the observance then – or now, Waskow said. Some were troubled by what they viewed as a distortion of  Jewish history and sacred practice. But as a controversial activist who has written 24 books and been arrested as many times during protests, Waskow does not shrink from the harsh spotlight of controversy. He has criticized Israel's policy toward the Palestinians, upsetting some in the Jewish community, but he also has argued against a blanket boycott of Israel. He favors a two-state solution.

Waskow writes a daily missive on current events for the Shalom Center, his nonprofit peace and justice organization that also advocates for environmental sustainability. His email list has more than 10,000 subscribers.

Abby Stamelman Hocky, executive director of the Interfaith Center of Greater Philadelphia, said Haggadah such as the Freedom Seder "awaken us to the unfulfilled promise of our nation."

"In retelling the Passover story," Hocky said, "we must do so in a way that breaks open our hearts to the cries of injustice, and moves us to action."

In the MLK+50 version, Waskow takes the custom of drinking four cups of wine, symbolizing the four ways God promised to deliver the Jews, and ascribes different meanings. The four glasses represent the eradication of the three evils King outlined in his 1967 "Beyond Vietnam: A Time to Break Silence" speech: racism, militarism and materialism.  The fourth cup is dedicated to ending the subjugation of women.

Gabriela Sanchez, founder and managing director of Power Street Theatre Company, recites a poem at the National Museum of American Jewish History’s Freedom Seder celebration.
TOM GRALISH / Staff Photogapher
Gabriela Sanchez, founder and managing director of Power Street Theatre Company, recites a poem at the National Museum of American Jewish History’s Freedom Seder celebration.

On Monday, the Jewish museum's Freedom Seder celebration included artists and musicians describing what freedom meant to them.

Gabriela Sanchez, founder of Power Street Theatre Company, said she "breaks free" through her poetry. Musician Stanford L. Thompson, founder of Play On, Philly!, a youth development program, recounted growing up in Atlanta immersed in the ethos of King and the Civil Rights movement. Eppchez Yo-Si Yes, founder of Alma's Engine theater company in West Philadelphia, applied the symbolic foods on the Passover plate to the LGBT struggle for liberation.

Stanford L. Thompson, founder and executive director of Play On, Philly! performs at the seder.
TOM GRALISH / Staff Photographer
Stanford L. Thompson, founder and executive director of Play On, Philly! performs at the seder.

To assure that the MLK+50 Seder will flourish as the first did, Waskow will discuss it at several Passover events, including a Seder on Thursday at Mishkan Shalom synagogue in Philadelphia.

"I hope people will use it as a whole or choose passages to use in their own seders," he said. "Beyond that, I hope they will commit themselves to act — and act on the things they commit themselves to."