It's hard to imagine that anything literally hanging from utility poles across Manhattan could be considered "hidden." But throughout the borough, about 18 miles of translucent wire stretches around the skyline, and most people have likely never noticed. It's called an eruv (pronounced “ay-rube”) and its existence is thanks to the Jewish Sabbath.

On the Sabbath, which is viewed as a day of rest, observant Jewish people aren't allowed to carry anything—books, groceries, even children—outside the home (doing so is considered "work"). The eruv encircles much of Manhattan, acting as a symbolic boundary that turns the very public streets of the city into a private space, much like one's own home. This allows people to freely communicate and socialize on the Sabbath—and carry whatever they please—without having to worry about breaking Jewish law.

As the writer Sharonne Cohen explains, eruvin were created by “the sages of the Talmud” to get around traditional prohibitions on carrying “house keys, prayer books, canes or walkers, and even children who cannot walk on their own.” New York City isn't the only metropolis in the US with an eruv. They are also in St. Louis, Atlanta, Baltimore, Chicago, Dallas, and numerous other cities across the country.

A cynic might wonder at the effort required to string wire around huge swaths of public space, in order to allow adherents of a religion to do what the tenets of that religion would otherwise prohibit. Even some religiously-minded observers might find it hard to imagine a God that wouldn’t regard this as the flagrant concoction of a city-sized loophole.

Possible Preaching Angle:

1) Excuses; Rationalization - We might shake our heads to think that anyone could believe that they could get around God’s law using this scheme. But in retrospect, aren’t we guilty of the same thing when we push the boundaries and think that we can get away with finding a loophole in God’s laws when we sin? 2) Jewish People; Law; Sabbath - As a positive illustration, this might be a loophole but at least this story shows how seriously our Jewish friends take their commitment to honor the Sabbath.

Rabbi Adam Mintz, co-president of the Manhattan eruv, talks more about it in this video.