Shabbat 151A

האי ״כל שאני זכאי באמירתו רשאי אני בחשיכתו״? ״כל שאיני זכאי באמירתו איני רשאי בחשיכתו״ מיבעי ליה! אלא אסיפא קאי: ״אבל מחשיך הוא לשמור ומביא פירות בידו״⁠ — האי ״כל שאני זכאי בחשיכתו רשאי אני באמירתו״ מיבעי ליה!

this phrase: Anything that I am permitted to discuss on Shabbat I am permitted to wait for nightfall for its sake, is not appropriate. Rather, the Mishnah should have formulated the principle in the negative: With regard to anything that I am not permitted to discuss on Shabbat, I am not permitted to wait for nightfall for its sake, similar to the phraseology at the beginning of the Mishnah. Rather, it is referring to the latter clause of the Mishnah, which taught: But he may wait for nightfall in order to guard his produce, and he may bring produce in his hand. But even if this is correct, the phraseology does not fit. It should have said the opposite: Anything for which I am permitted to wait for nightfall I am permitted to discuss.

לעולם אסיפא קאי, ואבא שאול אהא קאי דאמר רב יהודה אמר שמואל: מותר לאדם לומר לחבירו ״שמור לי פירות שבתחומך, ואני אשמור לך פירות שבתחומי״. וקאמר אבא שאול לתנא קמא: מי לא מודית דמותר אדם לומר לחבירו: ״שמור לי פירות שבתחומך ואני אשמור לך פירות שבתחומי״.

The Talmud explains: Actually, it is referring to the latter clause of the Mishnah, and Abba Shaul relates to this statement that Rav Yehuda said that Shmuel said: It is permitted for a person to say to another on Shabbat: Guard my produce that is in your boundary for me, and I will guard your produce in my boundary for you. And this is what Abba Shaul said to the first tanna: Do you not agree that it is permitted for a person to say to another: Guard my produce that is in your boundary for me, and I will guard your produce that is in my boundary for you? It is in such a case that Abba Shaul permitted waiting for nightfall at the edge of the Shabbat boundary in order to guard produce.