The mishnah at the beginning of today’s daf declared that priests and Levites are exempt from the obligation of the firstborn from a kal v’chomer (a fortiori) inference: Since they exempted the Israelites’ firstborns in the wilderness from their sacred status, they should be able to render their own firstborns exempt.
The Gemara played out which type of firstborn the mishnah was referring to. The line from the Torah reads, “Take the Levites in exchange for all the firstborn among the children of Israel and the animals of the Levites in exchange for their animals” (Numbers 3:45). We see that the Levites themselves redeemed the sanctity of the Israelites’ firstborns, and the Levite animals redeemed the sanctity of the Israelites’ firstborn animals. Ultimately, we rule that priests and Levites are exempt both from pidyon haben (redeeming a firstborn child) and peter chamor (redeeming a firstborn donkey).
Apropos this discussion of firstborn status in the wilderness, our Gemara presents an amoraic dispute:
It was stated with regard to the sanctity of the firstborn in the wilderness: Rabbi Yohanan says that both firstborn animals and firstborn sons born in the wilderness were sanctified, and Reish Lakish says: The firstborn that were born in the wilderness were not sanctified.
Rabbi Yohanan says that the firstborn that were born in the wilderness were sanctified, since the Merciful One states they should be sanctified, as it is written prior to the Jews leaving Egypt: “Sanctify to Me all the firstborn” (Exodus 13:2).
And Reish Lakish says: The firstborn that were born in the wilderness were not sanctified, as it is written: “And it shall be when the Lord shall bring you into the land of the Canaanites” (Exodus 13:11), and it is written afterward: “And you shall set apart all firstborn of the womb to the Lord” (Exodus 13:12). By inference, it can be derived that initially, they were not sanctified.
Rabbi Yohanan and Reish Lakish dispute whether those firstborns who were born in the wilderness had sacred status. Both agree that the firstborns in Egypt were sanctified at the time of the command in Exodus 13, and both agree that firstborns were sanctified upon arriving in the land. But Reish Lakish thinks the wilderness constituted a gap and that any firstborn born in those 40 years had no special status, while Rabbi Yohanan thinks that once the firstborn sanctity was established in Egypt, it was never abrogated.
Rabbi Yohanan raised an objection to the opinion of Reish Lakish from a mishnah (Zevahim 112b): Until the tabernacle was established, private altars were permitted, and the sacrificial service was performed by the firstborn.
Reish Lakish said to him: That mishnah is referring to those firstborn who left Egypt.
Rabbi Yohanan attempts to prove from a mishnah in Zevahim that the firstborn of the wilderness were sacred: If it says the firstborn performed the sacrificial service prior to the tabernacle’s erection, wouldn’t that mean the firstborn of the wilderness had special status? Reish Lakish gives a seemingly obvious rebuttal: This could simply refer to the firstborns who were sanctified in Egypt before their departure. The Gemara supports his answer, pointing out that we in fact must be referring to those born in Egypt, because those born in the wilderness would have been less than a year old! This is such an obvious point that the Gemara asks a follow-up question:
And he who asked it, why did he ask it?
Why did Rabbi Yohanan even think this was a legitimate challenge? The Gemara answers:
This was his difficulty: Granted, if you say that the sanctity of the firstborn did not cease from the time that the mitzvah of: “Sanctify to Me all the firstborn” (Exodus 13:2) was given in Egypt, then with regard to these firstborn who were originally in Egypt, their sanctity also did not lapse. But if you say that the sanctity of the firstborn ceased and the firstborn born in the wilderness were not sanctified, then with regard to these firstborn that were originally born in Egypt, their sanctity also lapsed.
And the other amora, Reish Lakish, responded: Those who were sanctified in Egypt were sanctified, while those who were not sanctified in Egypt were not sanctified in the wilderness.
Rabbi Yohanan couldn’t envision a period in which some firstborns were sanctified and others were not. Therefore, he assumed that either all firstborns were sanctified — those born in Egypt and those born in the wilderness — or if the firstborns of the wilderness weren’t sanctified, then the sanctity of those born in Egypt was abrogated. Reish Lakish replies that there’s no reason for this assumption; it’s logically coherent to say that those sanctified in Egypt remained sanctified, while those born in the wilderness were not newly sanctified.
Reish Lakish and Rabbi Yohanan — and the Gemara arguing on their behalf — continue to throw out challenges and resolve them for each of their respective opinions. This tangent of the Gemara is an interesting example of a dispute that is related to our main topic, but ultimately does not have halakhic significance; since everyone agrees firstborns are consecrated after entering the land, the dispute is not about current status, but about a detail of the wilderness narrative. Nonetheless, the rabbis still believed these questions were worthy of exploring.
Read all of Bekhorot 4 on Sefaria.
This piece originally appeared in a My Jewish Learning Daf Yomi email newsletter sent on September 22, 2026. If you are interested in receiving the newsletter, sign up here.
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