The opening mishnah of Tractate Shevuot listed a series of four areas of law that can be categorized as “two types that are four” — that is, two categories that each subdivide into two more. Oaths, the topic of the current tractate, is the first. The other three are: defiling the Temple or its sacrificial foods while ritually impure and having some awareness, carrying on Shabbat and the appearance of marks of the skin disease tzaraat.
This is not the only mishnah that opens a tractate with a “two that are four” formula. Mishnah Shabbat opens with the statement about carrying and Mishnah Negaim begins with the formula applied to marks of tzaraat. But only our tractate collects all four categories and only our tractate discusses the first two at length. The Gemara, which sometimes begins with these kinds of meta-questions about the Mishnah’s organization, wants to know why:
What is different between here (in Shevuot) that the mishnah teaches all the sets of laws that can be formulated as “two that are four” and there (Shabbat and Negaim) that begin, “The acts of carrying out that are prohibited on Shabbat are two that are four” and “the shades of leprous marks are two that are four,” respectively, in which the mishnah does not teach all of them?
Why does this mishnah, in particular, bring in material apparently unrelated to oaths? And not only that, it then (as we saw yesterday) dwells largely on non-oath other material — the laws concerning defilement of the Temple. The Gemara answers its own question:
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Since the passages of oaths and of liability based on one’s awareness of the defiling of the Temple or its sacrificial foods are written together in the Torah (see Leviticus 5:2–4), and they are also similar to each other in that they can both incur liability to bring a sliding-scale offering, the mishnah therefore taught both of them together here. And once it already taught two sets, it continued and taught all of them.
It turns out that these first two apparently disconnected subjects — oaths and defiling the Temple with different levels of awareness — are actually connected in ways we might not have realized. First, the biblical passage about oaths is adjacent to the one about what to do upon becoming aware of a defiling of the Temple or its sacrificial foods (see Leviticus 5:2–4). Second, they share a common remedy: a guilt offering that can be chosen among a variety of animals, ensuring all are able to afford the sacrifice. Given these two connections, says the Gemara, the two sets of laws were treated side-by-side in Tractate Shavuot — even if the material on the defilement of the Temple may have thematically fit better into one of the tractates on sacrifices or purity. Moreover, since the mishnah here mentioned the first two categories of law in which “two are four,” the editor threw in the other two as well — though they are handled in other tractates so not discussed further here.
Before moving on to its discussion of the laws themselves, the Gemara has one more meta-question: Given that the mishnah mentions oaths before the cases of one’s awareness of the defiling of the Temple or its sacrificial foods, shouldn’t it treat them in the same order? Why are the first two chapters of the tractate discussing Temple defilement, returning only to the topic of oaths in chapter three? The Gemara explains this as well:
Since the cases of one’s awareness of the defiling of the Temple or its sacrificial foods are relatively few, the Mishnah addressed them directly and dispensed with them, and then afterward returned to teach the laws of oaths, which have numerous details.
A sensible decision. It’s not often that the Gemara takes us behind the curtain and shares insight into the editorial decisions that were made by those who codified the Mishnah. And if you’re ready to move past that discussion and dive into the subject-matter, you can look forward to that next.
Read all of Shevuot 3 on Sefaria.
This piece originally appeared in a My Jewish Learning Daf Yomi email newsletter sent on May 4, 2025. If you are interested in receiving the newsletter, sign up here.
