On the eve of World War II, the owner of a Belleville, New Jersey, paint shop got a frantic knock on his door. It was a 28-year-old German immigrant named Leo Gelbart, who’d been going door to door, appealing to members of the town’s Jewish community.

“This family needs to get out of Germany, and I don’t have enough money to help. Can you?” Gelbart asked. He showed the store owner a black-and-white photograph of his friends back in Munich: a handsome couple named Karl and Justine Penzias, holding their sons Arno and Guenther, six and four. With German Chancellor Adolf Hitler’s Nazi regime increasingly persecuting and interning Jews, the Penzias family had to flee or face a concentration camp. But to immigrate to America, they needed to secure several affidavits of support — official documents vouching that they had a relative and a financial safety net in the United States. Gelbart would provide the first, falsely stating that his friend Karl Penzias was his cousin. But as a waiter, he didn’t have enough money to qualify as the family’s sponsor. He was trying to find someone to sign the second affidavit taking on the Penziases as dependents in case of need.

The 52-year-old paint merchant said yes, he would help. “I’ll be glad to support them until they become self-supporting,” he wrote on the affidavit. From Germany, a deeply grateful Karl Penzias gave this stranger his word, via his friend, that his family only needed support on paper and would show their gratitude by never contacting him.

The older of the two boys in the photograph, Arno Penzias, is 89 now. A retired Nobel Laureate radio astronomer, he lives in northern California. He was born in Munich in 1933, as Hitler rose to power. In 1938 his family was rounded up with other Jews who held Polish passports and forced aboard a train to Poland for deportation. But their train was delayed, and Poland invalidated their passports just before their train reached the border.

In 1939, as they scrambled to make arrangements to leave Germany for America, Arno's parents sent their young sons to England as part of the Kindertransport, a British rescue effort that transported 10,000 mostly Jewish children out of Nazi territory. The brothers bounced around from an all-girls London orphanage to different English foster families. As Nazis accelerated Hitler’s murderous campaign that would give birth to the word “genocide,” Karl and Justine Penzias, equipped with the necessary paperwork, eventually reunited with their sons in England and set out for the U.S. by boat. The family dodged hurricanes and German submarines on their journey across the Atlantic. On January 3, 1940, as their ship docked in New York City, journalists snapped photographs of Arno and Guenther, wide-eyed young refugees waving to the Statue of Liberty.

"I came to the United States thirty-nine years ago as a penniless refugee from Nazi Germany. For my family and myself, America has meant a haven of safety as well as a land of freedom and opportunity. At a time when the promise and meaning of American institutions are often questioned, I feel compelled to bear witness to the fulfillment of the American promise in my personal life experience. I am very proud to be an American, very grateful to America and to the American people. Thus, in your capacity as a representative of the American people, I have taken this occasion to express a small portion of my thanks to them through you.”

But thanking the man whose signature opened the door to America wasn’t feasible. Arno’s father had promised never to contact the signer of the affidavit, and he kept his word. The details regarding their helper remained a mystery.

After some online searching, David Penzias dialed a number he found for a Robert Yudin in New Jersey, whom he was pretty sure was Barnet Yudin’s grandson. It was an unexpected call that led to a unique connection. The Yudins were taken aback at first; Barnet had died of cancer in 1950. His wife, son, and daughter were also deceased, and his grandchildren had no recollection of Barnet mentioning a German family he’d aided with an affidavit. But Arno’s son shared the documents, and the puzzle started to come together.

Barnet’s granddaughter Sydney Neuwirth, a retired artist in Princeton, New Jersey, grew up in one of the apartment’s her grandfather built above his paint shop. As she sifted through a binder of photos, letters, and newspaper clippings chronicling her grandparents’ lives, Neuwirth felt a deep connection to her grandfather and the family he helped spare. “He knew what it was like to be turned down, turned away,” Neuwirth says. “This was his way of helping. He always wanted to help.” As she reads about the war currently raging in Ukraine—and the resulting refugee crisis, Europe’s largest since World War II—she finds even more perspective.

Nearly eight decades after Barnet signed the affidavit, his family took David Penzias up on his request to get together. While Arno couldn’t join because of his declining health, his brother and nephew travelled to New Jersey for brunch at Barnet’s grandson’s home. Over a hearty spread of bagels, lox, and whitefish, the families shared documents and memories. David handed out copies of a recent photograph of his father and uncle with their direct descendants. As the Yudins studied the grey-haired patriarchs surrounded by their five grown children and ten grandkids, David said: “None of these people would exist today without Barnet Yudin.” Struck by the enormity of what Barnet’s quiet act enabled, a new friendship was born.