When I worked at a small daily newspaper in South Florida, the two major faith groups that I covered were Jews and Catholics. And these were plenty of Jewish readers who demanded articles with some degree of theological sophistication about their lives and beliefs.

While there was always the inevitable “best hamantaschen in Broward County” pieces, I also wrote about the building of a new eruv in a neighborhood with a fast-growing Orthodox Jewish community. Only in the Miami area — and several corners of New York City — could a religion writer cover the establishment of an eruv and have a large, vocal readership that knows what that is.

One problem with writing about an eruv is that the tradition started with the Talmud and trying to explain Talmudic law in a news story was like stepping into quicksand. You got sucked in by all the history and the details.

What is at stake was not just the eruv itself but explaining the Jewish laws that mandate Sabbath-keeping and set the stage for the building of an eruv in the first place. So I was glad to see that NPR tackled the topic in a recent report. The journalism question here is whether the story is long enough to get the job done.

A clear fishing wire is tied around the island of Manhattan. It's attached to posts around the perimeter of the city, from First Street to 126th. This string is part of an eruv, a Jewish symbolic enclosure. Most people walking on the streets of Manhattan do not notice it at all. But many observant Jews in Manhattan rely on this string to leave the house on the Sabbath.

The concept of the eruv was first established almost 2,000 years ago to allow Jews to more realistically follow the laws of Sabbath rest, particularly one — no carrying on the Sabbath.

Actually, there is no one Bible verse saying “Thou shalt not carry anything on the Sabbath.”

The closest is a verse in Jeremiah 17:21 that talks about not carrying things for sale during the Sabbath, but there’s nothing that really addresses what goes on domestically. Carrying isn’t mentioned in the traditional 39 activities prohibited on the Sabbath.

According to the laws of Sabbath rest, nothing can be carried from the domestic zone into the public zone on Saturday. That means no carrying house keys or a wallet. It also means no pushing a baby stroller. For parents of young children, no carrying would mean not leaving the house on Saturday.

The eruv symbolically extends the domestic zone into the public zone, permitting activities within it that would normally be forbidden to observant Jews on the Sabbath.

The story tells of Jews who have literally wrapped large chunks of Manhattan in string.

More than 200 cities around the world are partially encircled by an eruv. Manhattan's certainly isn't the largest, but according to Mintz, it's the most expensive eruv in the world. It costs between $125,000 and $150,000 a year to maintain. Mintz helps raise the funds every year from synagogues and private donations.

Every Thursday before dawn, a rabbi drives the perimeter, checking to see if wind or a fallen branch has broken the line. There are usually a few breaks, so a construction company is called and the rabbi gets in a cherry picker with fishing line in hand to repair the eruv. That's the part that costs so much.

Eruvs actually do make news and this 99PercentInvisible.org report from a year ago talks about how Mahwah, N.J., residents were up in arms over the construction of an eruv in their city. For some, efforts to create holy space is wonderful. For others, it is trespassing.

There’s all sorts of articles out there about the eruv (plural is eruvin) and how even the White House exists in one. Two years ago, the National Post ran a piece on eruvin in Canada, including eruv jokes.

Come to think of it, eruvin symbolize the profound concept of making public space sacred for Jews. It’s not as in-your-face as setting up menorahs in public places for Hanukkah, but it’s an important statement about life in the public square. As bigthink.com explains:

Both rooted in the desire to conform to God’s law and subject to nuts-and-bolts inspection and maintenance like any other public utility, eruvin are a curious hybrid of the divine and the mundane. To believers, they are of paramount ritual importance; to non-believers, it’s almost as if they weren’t there. This simultaneous existence and non-existence of eruvin is reminiscent of the quantum state of Schrödinger’s cat, both alive and dead in that box.

Schrödinger’s cat has to do with quantum physics. And that’s a whole lot tougher to explain in a news article than an eruv.

An eruv presupposes not only the existence of God but laws set up by God. If anything, the NPR piece was simply too short. There are all sorts of theological byways one can take while reporting on these invisible spiritual fences. And if you want to know where Orthodox Jews live in a particular city, check out an eruvin directory.

The short NPR piece is just a crack in the doorway of what can be written about these boundaries. Chances are they’re in a city near you.