He is a study in contrasts, with a penchant both for meditation and for hitting the gym five times a week. As a young man, he spent a few years in prison for burglaries in New York and New Jersey. “I had a really troubled youth,” he said. “It helped me understand some of the troubles others are going through.”

That empathy taught him a powerful lesson about hatred  and brought him national attention.

In 1991, he was living in Lincoln, Neb., with his wife at the time, Julie Michael, and three of their five children. He was then the cantor and spiritual leader of the South Street Temple, the oldest Jewish congregation in Lincoln. One Sunday morning, a few days after they had moved into their new house, the phone rang.

The man on the other end of the line called Rabbi Weisser “Jew boy” and told him he would be sorry he had moved in. Two days later, a thick package of anti-black, anti-Semitic pamphlets arrived in the mail, including an unsigned card that read, “The KKK is watching you, scum.”

Image Rabbi Michael Weisser, left, at a Friday night service at the Free Synagogue of Flushing, Queens. Credit... Richard Perry/The New York Times

The messages, it turned out, were from Larry Trapp, the Grand Dragon of the White Knights of the Ku Klux Klan in Nebraska, who kept loaded weapons, pro-Hitler material and his Klan robe in his cramped Lincoln apartment. Then 42, Mr. Trapp was nearly blind and used a wheelchair to get around; both of his legs had been amputated because of diabetes.

In a 1992 interview with Time magazine, Mr. Trapp said he had wanted to scare Rabbi Weisser into moving out of Lincoln. “As the state leader, the Grand Dragon, I did more than my share of work because I wanted to build up the state of Nebraska into a state as hateful as North Carolina and Florida,” he said. “I spent a lot of money and went out of my way to instill fear.”

Rabbi Weisser, who suspected the person threatening him was Mr. Trapp, got his telephone number and started leaving messages on the answering machine. “I would say things like: ‘Larry, there’s a lot of love out there. You’re not getting any of it. Don’t you want some?’ And hang up,” he said. “And, ‘Larry, why do you love the Nazis so much? They’d have killed you first because you’re disabled.’ And hang up. I did it once a week.”