Eruvin is considered to be one of the most difficult tractates in the Talmud, and for good reason — it is notoriously detailed and technical. And we get a taste of that on today’s daf.
On yesterday’s daf, the rabbis discussed whether the crossbeam on an alleyway entrance counted as an eruv if it was taller than 20 amot, normally translated as “cubits.” Today, the rabbis are deep in debate over another common talmudic unit of measurement — a tefach, or a handbreadth.
If we wanted to measure out centimeters or inches today, we would reach for a ruler marked at regular intervals. But the rabbis didn’t have standard measurements like we do. So they measured length and distance by body parts or human motion: a finger, a handbreadth, a pace. Jewish law is one way we make sense of God’s world, so just like the Torah, which lives and breathes alongside the Jewish people, these rabbinic measurements are also full of life.
They are also full of ambiguity. On the top of today’s page, we read this:
The Gemara raises an objection from a baraita: All cubits that were mentioned by the Sages are cubits of six handbreadths, provided that they are not precisely a cubit. Granted, according to Rava, the baraita means: So that these, the cubits of diverse kinds of seeds, should be measured with expansive handbreadths, and those, the cubits of sukkah, should be measured with depressed handbreadths.
According to Rava, what unit of measurement you use depends on what you’re measuring. If it’s seeds, you use an expansive handbreadth. If it’s a sukkah, you use a depressed one. What’s the difference? Expansive handbreadths are measured with the fingers spread apart, while depressed handbreadths are measured with the fingers held together.
Later on the daf, the rabbis debate whether the basis for all these various measurements can be found in the Torah, and one opinion traces their root to a surprising source.
Are measures a halacha transmitted to Moses from Sinai? They are written in the Torah, as it is written: “A land of wheat, and barley, and vines, and figs, and pomegranates, a land of olive oil and honey” (Deuteronomy 8:8), and Rav Ḥanan said: This entire verse was stated for the purpose of teaching measures with regard to different halachot in the Torah.
According to Rav Hanan, all the laws of measurements can be derived from a verse describing the sweetness and abundance of the promised land. How much can a person carry on Shabbat and not be liable? The volume of a dried fig. How broken must a vessel be such that it can no longer transmit ritual impurity? It must have a whole the size of a pomegranate. How large must a bone from a corpse be before it can impart ritual impurity? The size of a barleycorn.
While these discussions might seem cold and technical, they’re actually deeply human. Try learning today’s daf without demonstrating a spread fist or a relaxed one with your own hand, or by imagining the size of a pomegranate on your plate. Halachic life is a part of us. As we explore Eruvin together, let’s remember that there is deep spiritual knowledge, imagination and creativity behind these measures.