Eruvin 43

Joseph the demon.

Today’s daf features a discussion about whether the laws about Sabbath travel limits apply if one is somehow more than ten handbreadths above the ground. As part of this discussion, the rabbis cite a tradition that someone had once taught on Shabbat morning in the rabbinical academy at Sura and on Shabbat afternoon in the academy at Pumbedita.

According to Google maps, it would take 37 hours to walk from Sura to Pumbedita, two ancient cities in what is today Iraq. We can imagine that it might have taken even longer in the time of the rabbis. But according to this story, the same teacher taught rabbinic law in both centers on the same day. And to complicate things further, it was Shabbat, when travel of such a distance is prohibited. So how was it possible?

Some say that it was Elijah who said them, which proves that the law of Sabbath limits does not apply above ten handbreadths. 

In the Bible, we learn that the prophet Elijah ascended to heaven in a fiery chariot, which the rabbis imagine he then uses to get around in his long and storied afterlife. But the rabbis also raise a second possibility about the identity of the teacher:

No, perhaps the demon Joseph said them.

Wait, what? Who is Joseph the demon and why would he be teaching Torah in rabbinic centers on Shabbat?!

This question is one that readers of today’s daf have asked for hundreds of years. Some medieval commentators suggested that Joseph was not actually a demon but a human, and that this name – the demon – was just a nickname. But that doesn’t really help clarify matters: How could a human have traveled 37 hours in a single day?

Many of the modern English translations of today’s daf, including the one we usually use in this series, find the idea of a demon teaching Torah in these rabbinic centers so weird that they explain the matter this way: As a demon, Joseph does not observe Shabbat and so could travel long distances with impunity. But if Joseph is not bound by Jewish law, then why is he teaching it in rabbinic communities? And why are his teachings welcomed by the great sages of the day?

But the original text of the Talmud doesn’t include this idea, as you can see from the more literal translation above.

Joseph the demon actually appears elsewhere in the Babylonian Talmud, in Tractate Pesachim, where we encounter two of his teachings. We also have evidence of Joseph from a non-talmudic source from the same time period – a clay bowl inscribed in Aramaic with an incantation against danger, including dangerous demons. On this one bowl, the scribe lists a number of powerful rabbis who historically fought against the threat of demons. One of those listed is none other than Rabbi Joseph the demon.

Apparently, Joseph the demon is a rabbinic informant and a teacher of rabbis, and perhaps even a rabbi himself! In their discussion of the laws of Sabbath limits, then, the rabbis are so confident in the amazing power and welcome of the rabbinic community that they assume that everyone in the world – human and otherwise – would want to be part of it. Now that’s a big tent!

Read all of Eruvin 43 on Sefaria.

This piece originally appeared in a My Jewish Learning Daf Yomi email newsletter sent on September 21, 2020. If you are interested in receiving the newsletter, sign up here.

Discover More

Introduction to Halacha, the Jewish Legal Tradition

Halacha, from the Hebrew word for "walking" or "path," is the rabbinic interpretation of Jewish law.

Understanding Viddui

Reciting this prayer of confession is among the core requirements of Yom Kippur.

Talmud Words and Phrases

Essential vocabulary for understanding the Talmud.