Over the past year, controversies concerning the collection of user data by Facebook and other websites have raised questions concerning the preservation of privacy in the digital age. The increasing ubiquity of security cameras and the advent of the so-called Internet of Things—systems that allow household appliances, doors, heating systems, and so forth to be controlled by laptop and cell phone—pose even greater privacy concerns. Examining traditional Jewish law, or halakhah, for a concept of the right to privacy, Aviad Hacohen and Gabi Siboni suggest that secular Israeli law could learn from it in dealing with these challenges:

The ban on infringing upon a person’s privacy is specifically mentioned in Jewish law in many contexts. . . . For example, the Mishnah states, “A person must not create an opening [in his own house] opposite an opening [in his neighbor’s], or a window opposite a window. If his opening or window is small, he must not make it larger. If there is one opening, he must not turn it into two openings.” . . . In his commentary on the Talmud, Rabbi Shmuel ben Meir explains that the ban on creating a new opening opposite the opening to his neighbor’s yard (or even a yard shared by both of them) is designed to prevent damage caused by looking into another person’s property; that is, infringement on another person’s privacy.

[The contemporary scholar] Eliyahu Lifshitz explains that the Mishnah shows that damage to privacy caused by opening a window opposite a shared yard is relative and not absolute damage. For this reason, there is no requirement to conceal an existing window, even a large one; it is merely forbidden to create a new window or enlarge an existing one. If the window existed even before the neighbors moved in, they cannot force the window-owner to change his situation; rather, they must take their own measures to prevent the infringement of their privacy. . . .

Jewish law took a more significant step in protecting a person’s privacy regarding personal documents—such as medical records, letters, and, nowadays, material stored on a personal computer—based on a ruling by Rabbi Gershom ben Judah, the greatest Jewish sage in Germany in the 10th century. Among other things, he enacted a ban against any person who reads someone else’s letters without permission, since doing so invades the letter-writer’s privacy. . . .

The general prohibition against infringing upon privacy as well as the specific prohibition against accessing another’s records without that person’s explicit consent are therefore deeply rooted in Jewish law. Accelerated technological development, the weaknesses of cyberspace, and difficulties in security pose new and exciting challenges to Jewish law concerning the application of ancient principles to our times—pouring the fine old wine of Jewish law into the new container of the legal system in Israel, whose values are both Jewish and democratic.

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.