Moed Katan 2B

דלמא אתי לאינפולי. אבל מעיין שלא יצא בתחילה, דלא אתי לאינפולי ⁠— אפילו בית הבעל נמי!

as it is likely to collapse. But in the case of a spring that did not just emerge, which is not likely to collapse because its walls have already stabilized, even a field that ordinarily suffices with rainwater may be irrigated.

אם כן ⁠— מתניתין אמאן תרמייה? אלא: לרבי יהודה לא שנא מעיין שיצא בתחילה, ולא שנא מעיין שלא יצא בתחילה, בית השלחין ⁠— אין, בית הבעל ⁠— לא. והאי דקתני מעיין שיצא בתחילה, להודיעך כחו דרבי מאיר, דאפילו מעיין היוצא בתחילה ⁠— משקין ממנו אפילו שדה הבעל.

The Talmud asks: If that were so, then to whom, i.e., to which tanna, would you attribute the Mishnah? According to this interpretation, the Mishnah does not correspond to any opinion, while according to the previous interpretation, it corresponds to the opinion of R' Yehuda. Rather, it must be that according to the opinion of R' Yehuda, a newly emerged spring is no different from a spring that did not just emerge. A field that requires irrigation, yes, it may be irrigated, while a field that suffices with rainwater, no, it may not be irrigated. And the baraita opted to teach this dispute in the case of a newly emerged spring in order to convey the far-reaching nature of the opinion of R' Meir, which states that one may irrigate even from a newly emerged spring, and even a field that suffices with rainwater.

אתמר: המנכש והמשקה מים לזרעים בשבת, משום מאי מתרינן ביה? רבה אמר: משום חורש. רב יוסף אמר: משום זורע.

§ It was stated that the amora’im disputed the following question: With regard to one who weeds or one who waters seedlings on Shabbat, for what prohibited labor do we forewarn him? Judicial punishment may be administered to a sinner only if he has been forewarned by two witnesses prior to the commission of his offense. This forewarning must include the specific transgression being violated, and on Shabbat it must include the specific category of prohibited labor that the action involves. Rabba said: It is due to the prohibition against plowing. Rav Yosef said: It is due to the prohibition against sowing.