Bava Kamma 119A

מדאמר ״בכל מקום״, שמע מינה אסיפא קאי, ולקולא! שמע מינה.

From the fact that he stated that 4 or 5 animals may always be purchased, conclude from it that R' Yehuda’s statement is referring to the latter clause, and his statement is a leniency. The Talmud affirms: Conclude from it that R' Yehuda intended his statement as a leniency.

ולא משומרי פירות כו׳. רבא זבין שבישתא מאריסא. אמר ליה אביי, והא תנן: ולא משומרי פירות ⁠– עצים ופירות! אמר ליה: הני מילי בשומר, דלית ליה בגופא דארעא מידי; אבל אריס, דאית ליה בגוויה ⁠– אימא מדנפשיה קא מזבין.

§ The Mishnah teaches: And similarly, one may not purchase wood and produce from produce watchmen. The Talmud relates that Rava purchased grapevine branches from a sharecropper. Abaye said to him: But didn’t we learn in the Mishnah: And similarly, one may not purchase wood and produce from produce watchmen? The same halakha should apply with regard to a sharecropper, who, like a watchman, is not the owner of the produce. Rav said to him: This statement applies only with regard to a watchman, as he has no share at all in the land itself. But with regard to a sharecropper, who does have a share in it, say: He is selling merchandise from his own share of the land. Since it is plausible that the sharecropper is selling his own property, it is permitted to buy it from him.

תנו רבנן: שומרי פירות ⁠– לוקחין מהן כשהן יושבין ומוכרין, והסלין לפניהם, וטורטני לפניהם. וכולן שאמרו: ״הטמן״⁠ – אסור. לוקחין מהן מפתח הגינה, אבל לא מאחורי הגינה.

The Talmud cites a baraita which discusses purchasing items from watchmen: A baraita states (Tosefta 11:8): With regard to produce watchmen, one may purchase produce from them when they are sitting and selling the produce, and the baskets are before them and the scales [veturtanei] are before them, as in these circumstances it is reasonable to assume that they are not selling stolen merchandise. But in all cases where they said to the buyer: Conceal your purchase, it is prohibited to purchase from them, as there is good reason to suspect that the merchandise is stolen. The baraita adds: One may purchase from a watchman from the entrance of the garden, but not from the back of the garden, because if the produce is being sold inconspicuously, there is a concern that it might have been stolen.