The holiday of Purim, which began last night and continues today, is one of the most joyous days of the Jewish calendar, traditionally celebrated with carnival-like merriment. Yet, notes Meir Soloveichik, the story behind the holiday—recorded in the book of Esther—is an ominous one, in which a king cavalierly assents to a proposal of genocide on the part of his chief adviser and then, on the turn of a dime, changes his mind and has the adviser hanged:

The disquieting conclusion of Esther’s tale was eloquently described by my great-uncle, Rabbi Joseph B. Soloveitchik. “If a prime minister who just yesterday enjoyed the full confidence and trust of the king was suddenly convicted and executed,” he reflected, “then who is wise and clairvoyant enough to assure us that the same unreasonable, absurd, neurotic change of mood and mind will not repeat itself?” The Purim tale reminds us that a government, and the society it oversees, can turn against its most vulnerable in a matter of moments. This is why, he argued, Esther’s story is no triumphal tale; on the contrary, it is “the book of the vulnerability of man in general and specifically of the vulnerability of the Jew.”

Why, then, all the joy?

Here we must understand how different the book of Esther is from every other book in the Hebrew Bible. In this tale no mention is made of the divine; the Jews inhabit a world devoid of revelation. Whereas in every other scriptural tale political engagements take place under prophetic instruction, in the Persian court God gives no guidance to the Jews facing a terrible danger. Esther, Rabbi Soloveitchik wrote, faced an unprecedented question: “How can the Jew triumph over his adversaries and enemies if God has stopped speaking to him, if the cryptic messages he receives remain unintelligible and incomprehensible?”

In this sense, Esther is the first biblical figure, male or female, to engage in statesmanship. Previous heroes—Moses and Elijah, Samuel and Deborah—are prophets who are guided and guarded by the Divine, but Esther operates on instinct, reflecting a mastery of realpolitik.

Purim thus marks the fragility of Jewish security, but also the possibility of heroism in the face of this vulnerability. It is therefore a holiday for our time. Around the world, and especially in a Europe that should know better, anti-Semitism has made itself manifest once again. As Esther’s example is celebrated, and Jews gather in synagogue to study her terrifying tale, we are reminded why, in the face of hate, we remain vigilant—and why we continue to celebrate joyously all the same.

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.