Bava Batra 19A

לא משכחת ליה, אי בטרפא ⁠– הדר פארי.

the bees will not find it; if it is referring to a leaf, it will grow back.

ולא נברכת הכובסין וכו׳. אמר רב נחמן אמר רבה בר אבוה: לא שנו אלא מן המחמצן, אבל מן הנדיין ⁠– ארבע אמות. תניא נמי הכי: נברכת הכובסין ⁠– ארבע אמות. והא אנן תנן שלשה טפחים! אלא לאו ⁠– שמע מינה כדרב נחמן.

§ The Mishnah teaches: Nor may one set up a launderer’s pond near his neighbor’s wall unless he distances it 3 handbreadths from the wall. Rav Naḥman says that Rabba bar Avuh says: They taught this only with regard to a soaking pond, in which soiled clothes are left to soak for several days. But in the case of a washing pond [hanadyan], where clothes are actively cleaned, 4 cubits are required. That opinion is also taught in a baraita: A launderer’s pond must be kept 4 cubits from one’s neighbor’s wall. But didn’t we learn in the Mishnah that one must keep a distance of only 3 handbreadths? Rather, must one not conclude from the baraita that the statement of Rav Naḥman is correct?

ואיכא דרמי להו מירמי, תנן: נברכת הכובסין שלשה טפחים. והתניא ארבע אמות! אמר רב נחמן אמר רבה בר אבוה, לא קשיא: כאן מן המחמצן, כאן מן הנדיין. רב חייא בריה דרב אויא מתני לה בהדיא: אלא אם כן הרחיק משפת מחמצן ולכותל שלשה טפחים.

And some raise this as a contradiction, and present the Mishnah and baraita as apparently conflicting sources. We learned in the Mishnah that a launderer’s pond must be kept 3 handbreadths from his neighbor’s property. But isn’t it taught in a baraita that 4 cubits are required? Rav Naḥman says that Rabba bar Avuh says: This is not difficult. Here, the Mishnah is referring to a soaking pond, which requires 3 handbreadths; there, the baraita is referring to a washing pond, in which case 4 cubits are necessary. Rav Ḥiyya, son of Rav Avya, teaches the Mishnah explicitly as reading: Unless he distanced 3 handbreadths from the rim of the soaking pond and the wall.