My synagogue’s old prayer book hints at what these stories meant to American Jews Ms. Mallinger’s age. Its 1939 English preface to those stories of murdered rabbis asks : “Who can forget, even after decades, the sight of his father huddled in the great prayer shawl and trying in vain to conceal the tears which flowed down his cheeks during the recital of this poem?” By the time I was a kid reciting those poetic stories, no one was crying. Instead my siblings and I smirked at the excessive gory details, the violence unfamiliar enough to be absurd. But Rabbi Hanina must have been right, because we still were reading from that same scroll, the same words Jews first taught the world: Do not oppress the stranger. Love your neighbor as yourself.

People Ms. Mallinger’s age were in their 20s when word spread about mass murders of Jews in Europe. In synagogue on Rosh Hashana, they read the old words begging God for compassion, “for the sake of those killed for your holy name,” and “for the sake of those slaughtered for your uniqueness.” My husband’s grandparents came here after those massacres, their previous spouses and children slaughtered like the people in the prayer. They kept reciting the prayer, and for their new American family it reverted to metaphor.

In the decades that followed, Jews from other places joined American synagogues, many bringing memories that American Jews had forgotten. Those memories were waiting for them in the synagogue’s books. On the holiday of Purim, they recited the Book of Esther, about an ancient Persian leader’s failed attempt at a Jewish genocide. It’s a time for costumes and levity, for shaking noisemakers to blot out the evildoer’s name. One year my brother dressed as the ayatollah, and the Persians in our congregation laughed. Another year someone dressed as Gorbachev; the Russians loved it. The evildoers seemed defeated.

In 2000, when Ms. Mallinger was 79, a Jewish senator was his party’s nominee for vice president. A year later the White House hosted its first official Hanukkah party. About a decade later I attended one myself. In the White House we recited ancient words thanking God for rescuing us from hatred. To older Jews, this felt miraculous: My parents and grandfather gawked at my photos, awe-struck . But at the party I met younger Jewish leaders who often attended these events. To them, this was normal. The ancient hatred was a memory, words on a page.

Or maybe it wasn’t. In 2001, after terrorists attacked American cities, concrete barriers sprouted in front of my family’s synagogue , police cruisers parked in the lot. This felt practical in a nation on edge; we assumed it affected everyone. As my children were born and grew, the barriers and guards became their normal. When I took my children to an interfaith Thanksgiving service at a church down the street from our synagogue, one of them asked me why no one was guarding the door.