I Am Joseph Your Brother: The Untold Story Behind Nostra Aetate

A dying note smuggled from Auschwitz, an aging Jewish scholar in hiding, and a Pope determined to change history…

Angelo Giuseppe Roncalli—later known as Pope John XXIII—was more than a pontiff; he was a bridge-builder in a fractured world.

During World War II, he quietly helped Jews escape Nazi persecution, supported Jewish immigration to Palestine, and later championed the establishment of the State of Israel.

His papacy would ignite a revolution within the Catholic Church, culminating in the Second Vatican Council and its landmark declaration Nostra Aetate, which repudiated centuries of anti-Jewish prejudice and opened the door to Christian-Jewish dialogue.

Pope John XXIII died exactly 63 years ago-on June 3, 1963, but his legacy endures. And behind that legacy stands another remarkable figure: Jules Isaac.

I recently came across a copy of The Teaching of Contempt by French-Jewish historian Jules Isaac—a slim, 154-page volume distilled from his monumental work Jesus et Israel. First published in France in 1962 and later translated into English, Isaac’s book was born of tragedy and perseverance.

Before the war, Isaac was a towering figure in French education. As Inspector General of Public Instruction, he oversaw curricula used in virtually every French school. But in 1940, Nazi occupation stripped him of his position. By 1941, Isaac and his family were in hiding, hunted for their Jewish identity. At 64, Isaac turned his historian’s lens toward theology, determined to uncover the roots of the hatred that had engulfed Europe.

His research revealed a chilling truth: centuries of Christian teaching had sown contempt for Jews. Fluent in Greek, Isaac pored over the Gospels in their original language, comparing them with Catholic and Protestant commentaries. Over three harrowing years—while fleeing from one hiding place to another—he wrote Jesus et Israel, a 600-page indictment of theological anti-Judaism.

Then came personal catastrophe. In 1943, the Gestapo arrested Isaac’s wife, daughter, son-in-law, and one son. All but one perished in Auschwitz. Isaac survived, sustained by a note his wife managed to send before her death:
“Jules, take care of yourself, have confidence and finish your work. The world is waiting for it.”

He did. In 1946, Isaac completed his book, dedicating it to his murdered family:
“In Memoriam to my wife and my daughter, martyrs killed by Hitler’s Nazis, killed simply because their name was Isaac.”

Isaac coined the phrase “the teaching of contempt” to describe the centuries-old Christian attitudes toward Jews. His work was not merely academic; it was a moral summons. “It is the cry of an outraged conscience, of a lacerated heart,” he wrote, urging Christians to confront their complicity in anti-Judaism.

His ideas reverberated across Europe, reaching the Vatican. In 1960, at age 83, Isaac met Pope John XXIII for the second time. At the end of their warm conversation, Isaac asked, “May I carry away a bit of hope?” The Pope replied:
“You have a right to more than hope!”

That meeting became the spark for Nostra Aetate—the groundbreaking declaration of 1965 that shattered nearly two millennia of hostility and affirmed the Church’s respect for Judaism.

Neither Isaac nor Pope John lived to see the document’s publication. Isaac died in September 1963; the Pope three months earlier. Yet their courage and vision reshaped history.

When Pope John XXIII greeted a delegation of American Jews with the words, “I am Joseph your brother,” he spoke not only for himself but for a Church seeking redemption. His openness, coupled with Jules Isaac’s relentless scholarship and personal sacrifice, paved the way for Nostra Aetate—a declaration that ended centuries of enmity and affirmed the dignity of dialogue.

Their lives remind us that even in times of darkness, truth and compassion can prevail.

The world is still waiting for such voices today.