On today’s daf, we learn this from a mishnah:
(If the priest) pinched (the nape of the bird’s neck properly) and then it was found to be a tereifa (an animal that has an injury or illness that will cause its death), Rabbi Meir says: (An olive-bulk) does not render it ritually impure when it is in the throat. Rabbi Yehuda says: It renders it ritually impure.
To understand this mishnah, it is helpful to keep a few things in mind: (1) Consuming the meat of an animal that has not been properly slaughtered leaves a person in a state of ritual impurity, and (2) an animal that is slaughtered in order to be sacrificed and found after the fact to have a fatal condition is ineligible to be offered. In the latter case, the ritual slaughter purifies the animal so that its meat does not render a person impure if they eat it.
According to Rabbi Meir, this rule applies to birds who were slaughtered by pinching the neck. Rabbi Yehuda disagrees, holding that a bird that dies by pinching conveys impurity.
Rabbi Meir defends his position by using a kal vachomer, a logical argument that makes an inference from a lesser case to a greater one (or vice versa). He reminds us that an animal carcass normally causes those who touch or carry it to become impure, but this is not the case for a bird carcass. So if an animal carcass (about which the rules are stricter) no longer conducts impurity after ritual slaughter, so too should a bird carcass (about which the rules of impurity are less strict). And since pinching the neck is a form of ritual slaughter, this should be true for a bird whose neck was pinched.
In its discussion of this mishnah, the Gemara shares the biblical source for the kal vachomer, Numbers 12:14. The narrative preceding this verse relays that Moses has taken a foreign wife and his siblings have spoken out against him. God expresses support for Moses and afflicts his sister Miriam with a skin disease as punishment. Moses prays for her recovery and God’s response is presented in our verse: “If her father had but spit in her face, should she not be ashamed for seven days? Let her be shut out from the camp for seven days, and after that let her be received in again.”
Did you catch the kal vachomer? If Miriam had been rebuked by her father, God says, her embarrassment would lead her to remove herself from the public sphere for a week. Now that she has been rebuked by God, an authority figure of higher status than a parent, should she not also leave the camp for seven days? This, says the Gemara, is the source that establishes kal vachomer as a legitimate interpretive principle.
At the same time, this explanation creates a challenge for Rabbi Meir. As Tosafot point out, if a person separates themselves for a week after being rebuked by a parent, it would make sense for them to do so forever after being rebuked by God, as God is infinitely more of an authority figure. Nevertheless, God sets the period of removal at a week, the same as it would be for a parent. This puts a limit on the use of a kal vachomer, namely:
It is sufficient for the (conclusion) that emerges from a kal vachomer to be like its source.
In other words, when we make an inference from a lesser case to a greater one (or vice versa), we cannot change the conclusion. This is modeled after the biblical example, where the length of the punishment was held at seven days, even as a case could be made for more. This challenges Rabbi Meir, who expanded the conclusion to include birds slaughtered by pinching.
Rabbi Meir began with the fact that an animal that is ritually slaughtered and discovered to be a treifa does not transmit impurity to those who eat from their meat. The kal vachomer allowed him to extend that rule to birds. But the limiting rule says that the new rule has to be the same as the original one. Since animals are ritually slaughtered with knives, the rule should only apply to situations in which birds are slaughtered with a knife. But Rabbi Meir applies it to ritual slaughter of birds, which is done by pinching the neck with a fingernail — not with a knife. And so the kal vachomer doesn’t work because the conclusion is not like its source.
Rabbi Meir does not respond directly to this challenge, perhaps because he does not hold by the limiting principle. Rabbi Yosi the son of Rabbi Avin suggests that a kal vachomer is not necessary in this case because there’s a verse that can be used to support Rabbi Meir’s position.
But the more significant conclusion from today’s daf is that while the rabbis could create a new kal vachomer when the situation calls for it (which is not the case for all interpretive principles, see Nedarim 19b), they were also aware that without limits, a kal vachomer could be taken too far. Drawing from God’s example in Numbers 15, they limit the application of the principle. We can infer from a minor case to a major one (and vice versa), but the conclusion that emerges must match the source.
Read all of Zevachim 69 on Sefaria.
This piece originally appeared in a My Jewish Learning Daf Yomi email newsletter sent on November 22, 2025. If you are interested in receiving the newsletter, sign up here.
