In the West, perhaps no tune is so associated with Jews and Judaism as “Hava Nagilah” (“Let us rejoice!”), written by Abraham Zvi Idelsohn in the early 20th century. Born in 1882 in what is now Latvia, Idelsohn trained as a cantor before studying music formally at German conservatories. He then settled in Jerusalem. Edwin Seroussi and James Loeffler explain how he came to write “Hava Nagilah.”

Living next door to Eliezer Ben-Yehuda, the father of modern Hebrew, Idelsohn set as his own goal the creation of a modern Hebrew music to accompany the national rebirth of Jewish life in the ancient homeland. In the spirit of the Zionist philosopher Ahad Ha’am, Idelsohn began to collect all the riches of Jewish musical traditions that he found in Ottoman Palestine and throughout the Diaspora.

Using the emerging recording technology, he began to transcribe folk songs and make field recordings in order to forge an old-new musical sound that would be (in his view) authentically Jewish. That meant uncovering what he imagined to be the oldest layer of pre-exilic melody common to all Jewish traditions and liberating it from the foreign accretions resulting from the exile.

Like other architects of this new Hebrew culture, Idelsohn sought out Jewish religious culture in order to refashion it into new secular national traditions. It was in this context that Idelsohn premiered a new song, “Hava Nagila,” at a mixed-sex choir concert in Jerusalem sometime in 1918. . . . Much later, in 1932, Idelsohn wrote that he originally transcribed the melody from a Sadegurer Ḥasid in Jerusalem in 1915.

There are several possible explanations as to how and where Idelsohn encountered this Ḥasid. A recently catalogued collection of his papers, which had languished for decades in the library of Hebrew Union College in Cincinnati, seem to suggest the meeting took place even earlier.

Two extraordinary events demonstrate something important about Israel’s most fervent adversaries. One was a speech given at something called The People’s Forum (funded generously by Goldman Sachs), which stated, “When the state of Israel is finally destroyed and erased from history, that will be the single most important blow we can give to destroying capitalism and imperialism.”

The suggestion that this tiny state is the linchpin of a global, centuries-old phenomenon like capitalism goes well beyond anything resembling rational criticism. Even if Israel were guilty of genocide, apartheid, and oppression—which of course it is not—it would not follow that its destruction would help end capitalism or imperialism.

The other was an anti-Israel protest that took place in front of New York City’s Memorial Sloan Kettering Cancer Center, deemed “complicit” in Israel’s evils. At organizers’ urging, participants shouted their slogans at kids in the cancer ward, who were watching from the windows. Given Hamas’s indifference toward the lives of Gazan children, such callousness toward non-Palestinian children from Hamas’s Western allies shouldn’t be surprising. The protest—like the abovementioned speech—deliberately conveyed the message that Israel is the ultimate evil and its destruction the ultimate good, cancer patients be damned.

The fact that Israel’s adversaries are almost comically perverse does not mean that they can be dismissed. If its allies fail to understand the obsessive and irrational hatred that it faces, they cannot effectively help it defend itself.