Every day, starting 50 days before Passover, Ditza Or has been taking time to actively envision the moment her 30-year-old son, Avinatan, will join her and her family at the Seder.

She is not alone. United by WhatsApp groups, thousands of people have joined her in the daily exercise, inspired by the Chassidic teaching, “Think good, and it will be good.”

With less than two weeks to Passover, Or is among several mothers of hostages believed to be held in the Gaza Strip who have called upon the global Jewish community to invite as many Jews as possible to the Seder in the merit of the safe return of their loved ones.

In a video released through Chabad.org, Rachel Goldberg-Polin, the mother of hostage Hersh Goldberg-Polin, called for “people all over the world to invite as many people as possible to join them for Seder. We are praying that Hersh will be home for Seder, and it could be that in merit of you inviting people to your Seder, Hersh will return to us even before Pesach comes.”

Since the abduction of some 250 men, women, and children from southern Israel on Oct. 7 (an expected 133 are still there after the release of 105 hostages in November), Chabad emissaries in Israel and abroad have been a constant source of support and encouragement for the families of hostages. This effort, coordinated by Chabad.org, is steadily gaining momentum and galvanizing Jewish people around the world to act.

United under the hashtag #SeatAtTheSeder, the campaign was inspired by the Rebbe’s response to the Soviet Union’s decades-long refusal to allow Jews to immigrate to the West, where they would be free to practice their religion.

At several points in the 1970s, when some Jewish organizations suggested placing an empty chair at Seder tables in protest, the Rebbe spoke out publicly, instead urging world Jewry to add chairs and fill them in merit of those unable to attend.

This approach is also evident in the Rebbe’s oft-repeated clarion call to invite in the “fifth son,” the Jew who is so estranged from Judaism that he or she does not even attend the Passover Seder.

The current campaign takes its cue from the Rebbe’s empowering message. In the words of Goldberg-Polin: “There should be no empty seats at anyone’s Seder.”

Looking to get involved? Pull out your phone—or Rolodex—and start making invites. And then post on social media with the hashtag #SeatAtTheSeder so that others can do the same.