One of 39 prohibited melahot (labors) on Shabbat is carrying an object from a reshut hayahid (a private domain) to a reshut harabim (a public domain). The Torah does permit carrying within the reshut hayahid itself. Therefore, precise definition of reshut hayahid and reshut harabim is crucial to the laws of carrying on Shabbat. 39 prohibited melahot (labors) on Shabbat is carrying an object from a reshut hayahid (a private domain) to a reshut harabim (a public domain). The Torah does permit carrying within the reshut hayahid itself. Therefore, precise definition of reshut hayahid and reshut harabim is crucial to the laws of carrying on Shabbat.

Most streets, which are surrounded by three walls, are considered by the Torah to be a reshut hayahid. For areas that are not naturally enclosed, there is the erub.

The purpose of an erub is to enclose the area in question on all sides so that it becomes a reshut hayahid. Most modern erubim utilize pre-existing structures such as walls, fences, embankments, sides of buildings and long spans of cables.

In 1959, Menachem Kasher, a New York rabbi, declared that the sea walls and piers surrounding Manhattan constituted a suitable erub, making the entire island a reshut hayahid. Still, various smaller erubim were constructed within the sea wall erub. At one point, before the dismantling of the old Third Avenue commuter train line in 1955, the elevated tracks formed the western side of an erub used by the immigrant Polish Hasidic community. In 1994, Manhattan got its first erub on the Upper West Side. It was later extended to the East River and south to the 50s.

In 2005, 46 years after the sea walls were declared a natural erub, erosion led rabbis to declare it unacceptable. All of Manhattan was no longer an erub.

The Upper West Side Erub was built in the late 1990s. It went from the low 60s to either 107th or 108th Street depending on the block, and from Central Park West to Riverside Drive. The part of this erub on Central Park West was taken down each year before the Macy's Thanksgiving Day Parade, so the balloons could be inflated.

In 2004 there was a substantial expansion of the Upper West Side Erub and it was renamed the Upper Manhattan Erub. The expansion was from Central Park West to the East River, permitting carrying in Central Park and throughout a large part of the Upper East Side. The expansion also moved the erub south into the high 50s and north of Central Park. This removed the need to take down the erub for the Thanksgiving Day Parade.

Two years ago, Rabbi Yehuda Sarna of the Edgar M. Bronfman Center for Jewish Student Life at NYU, began a campaign to extend the Manhattan Erub farther south. It took two years, but it has finally happened. The erub has been extended from Midtown down to Houston Street.

Jonathan S. Nachmani, a trustee at Magen David of Union Square Synagogue, which helped organize the project, said the expansion would help keep the religious community vibrant. “Synagogue is going to be more of a social center for young married couples,” he said. This is because the change will greatly effect young congregants who are starting families. They will now be able to push strollers and carry diaper bags within the erub. The women will no longer be stuck at home with the babies.

Visit Manhattaneruv.org, every Friday, to make sure that the erub is up and running.