Study Eruvin folio 23A with parallel Hebrew-English text, traditional commentary, and modern study tools. Free access to Babylonian Talmud online.
Talmud: Rav Yosef said that Rav Yehuda said that Shmuel said: The halakha is in accordance with the opinion of R' Yehuda ben Bava. And Rav Yosef also said that Rav Yehuda said that Shmuel said: Upright boards surrounding a well were permitted only in the case of a well containing potable, running
The Talmud comments: And it was necessary to cite both of these statements, even though their content appears to be the same. As had he taught us only that the halakha is in accordance with the opinion of R' Yehuda ben Bava that upright boards may only be set arranged for a well, I would have said t
And that which was taught: One may only arrange boards for a public well, that was to exclude the opinion of R' Akiva that upright boards may be arranged even for a private well, but not to allow us to infer that boards may not be arranged for a public cistern filled with collected water. Therefor
And in the opposite direction, had he taught us that upright boards may only be arranged for a well containing potable, running spring water, I would have said that there is no difference whether it is a public well and there is no difference whether it is a private well. Shmuel therefore teaches us
Mishnah: And furthermore, R' Yehuda ben Bava said: With regard to a garden or a karpef, an enclosed courtyard used for storage, that is not more than 70 cubits and a remainder, a little more, as will be explained below, by 70 cubits and a remainder, and is surrounded by a wall 10 handbreadths hi