Eruvin 104B

תרו בה כיתנא ⁠— אסר להו.

they were soaking flax in the water, he prohibited them from drawing water by means of a wheel, so that they should not draw water for prohibited purposes.

ומבאר הקר. מאי באר הקר? אמר שמואל: בור שהקרו עליה דברים והתירוה.

We learned in the Mishnah that water may be drawn on a Festival from the Heker Well. The Talmud asks: What is the Heker Well? Shmuel said: It is a cistern with regard to which they advanced [hikru] arguments and permitted drawing water from it on a Festival, by proving that the Torah permits doing so.

מיתיבי: לא כל הבורות הקרות התירו, אלא זו בלבד. ואי אמרת ״שהקרו דברים עליה״, מאי ״זו בלבד״?

The Talmud raises an objection from a baraita: They did not permit all Heker wells, but only this one. And if you say it was named because it is a cistern with regard to which they put forward arguments and permitted it, what is the meaning of Heker wells in the plural, and what does only this one mean? If it was named because of a particular announcement, how could other wells, about which no announcement was issued, bear the same name?

אלא אמר רב נחמן בר יצחק: באר מים חיים, שנאמר: ״כהקיר ביר מימיה וגו׳״.

Rather, Rav Naḥman bar Yitzḥak said: The term Heker well denotes a well of living water, as it is stated: “As a well keeps its water fresh [hakir], so she keeps fresh her wickedness” (Jeremiah 6:7), i.e., it is a well of spring water.

גופא: לא כל הבורות הקרות התירו, אלא זו בלבד. וכשעלו בני הגולה חנו עליה, ונביאים שביניהן התירו להן. ולא נביאים שביניהן, אלא מנהג אבותם בידיהם.

Returning to the matter itself, the Talmud cites the above baraita in full: They did not permit all Heker wells, but only this one. And when the exiles ascended from Babylonia, they encamped by it, and the prophets among them, Haggai, Zechariah, and Malachi, permitted it to them. And it was not really the prophets among them who permitted them to draw water from this well on a Festival, but rather, it was a customary practice that was handed down to them from their forefathers, a practice the prophets permitted them to continue.