Bava Kamma 48A

מאי ברשות ומאי שלא ברשות איכא?

what reason is there to rule one way where the produce is brought in with permission, and what reason is there to rule another way where the produce is brought in without permission? With regard to damage done by the ox of a stranger, it should not make any difference.

אמרי: ברשות ⁠– הויא לה שן ברשות הניזק, ושן ברשות הניזק חייבת. שלא ברשות ⁠– הויא לה שן ברשות הרבים, ושן ברשות הרבים פטורה.

The rabbis said in response: If he brought in the produce with permission, it is a case of damage under the category of Eating (see 2a), in the domain of the injured party, since, with respect to the produce, the courtyard is treated as belonging to its owner, and the halakha is that if an animal causes damage categorized as Eating in the domain of the injured party, the ox’s owner is liable. But if he brought it into the courtyard without permission, it is a case of damage under the category of Eating in the public domain, and if an animal causes damage categorized as Eating in the public domain, the ox’s owner is exempt. Given this explanation, the answer to the question of what type of safeguarding the courtyard owner accepted cannot be derived from the baraita.

תא שמע: הכניס שורו לחצר בעל הבית שלא ברשות, ובא שור ממקום אחר ונגחו ⁠– פטור. ואם הכניס ברשות ⁠– חייב. מאן פטור ומאן חייב? לאו פטור בעל חצר, וחייב בעל חצר?

Come and hear a proof from another baraita: If one brought his ox into a homeowner’s courtyard without permission, and an ox from elsewhere comes and gores it, he is exempt. But if he brought it into the courtyard with permission, he is liable. The Talmud clarifies: Who is exempt and who is liable? Is it not the owner of the courtyard who is exempt and the owner of the courtyard who is liable? If so, this proves that the owner of the courtyard accepted responsibility for all damage occurring on his premises.