Why does the Torah insert the word "O ki Yichreh Ish Bor"?
Bava Kama, 48a: To Darshen "Ki Yichreh Ish Bor", 've'Lo Shor Bor'
Bava Kama (Ibid.): Not Reuven, because the Torah writes "ve'ha'Meis Yih'yeh Lo"
Seeing as one is Chayav even for removing the cover of a pit, why does the Torah need to add the Din of one who digs a pit? Why can we not learn it with a Kal va'Chomer from removing the cover?
Rashbam: Because the former is complete, whereas the latter is speaking where, at the end of the day, the pit is not completed, and he leaves it open to spare himself the trouble of covering it. Nevertheless, he is Chayav for subsequent damages. 4
Bava Kama, 3a: Because the Torah is speaking where he digs the pit in the R'shus ha'Rabim, in which case the pitt is npot legally his, and the Torah is teaching us here that he is nevertheless Chayav for digging or opening it. 5
Mechilta #1: We learn from here that 'Ein Onshin min ha'Din'. We can learn an Isur from a Kal va'Chomer, but not a punishment. So we need the Pasuk to teach us the punishment for someone who digs a pit.
Mechilta #2: To compare Koreh to Pose'ach - to render him Patur if he opens the pit with permission; 6 and Pose'ach to Koreh
Having taught us the Din of Shor, why does the Torah see fit to insert that of Bor? Why can we not learn it from Shor?
Mechilta: Because, unlike a Shor, which moves, a pit remains still and we would have not have known that its owner is Chayav, too.
Where is the pit for which he is Chayav, and for which he is Patur once he covers it?
Rashi and Targum Yonasan: In the R'shus ha'Rabim. 1
Or in any domain other than his own, in which case he is Patur - since he can claim 'What are you doing in my domain?' (Sifsei Chachamim).
Why does the Torah mention "Bor" twice?
Yerushalmi Bava Kama, 5:6: Once for Nizakin and once for Misah. 1
What are the implications of "ve'Lo Yechasenu"?
Bava Kama, 46a: It implies that if the owner covered the pit properly, he is no longer liable for subsequent damages. 1
Bava Kama, 55b: The Torah minimises the Shemirah, and only requires the owner to cover the pit, but not to fill it in.
See Torah Temimah, who discusses what is considered 'properly'.
If the owner hands an open pit to a Shomer Chinam, who is liable for damages?
Mechilta: The Shomer is liable, 1 since the onus now lies on him to cover it. And for the same reason someone who paints the pit, crafts pictures in it or whitewashes it is liable.
See Torah Temimah, note 258
What if an animal other than an ox or donkey fell into the pit?
Rashi (citing the Mechilta and Bava Kama): The owner of the pit pays for the damage to any animal. 1
Seeing as "Kesef Yashuv li'Be'alav" implies any animal that has an owner, why does the Torah specify "Shor O Chamor"?
Bava Kama, 54b: Because they are the most common animals to fit into the Pasuk.
"Shor" - 've'Lo Adam'; "Chamor" 've'Lo Keilim' (Rashi). See also Sifsei Chachamim, notes 4 & 5. In fact, if an ox or a donkey with its respective Keilim falls into the pit, and dies, and its Keilim break or tear, te owner is Chayav to par for the animal but Patur from paying for the Keilim (Bava Kama, 28b).
Since there is no reason to differentiate between a Bor (which is round), a trench, or a ditch, why does the Torah mention specifically "Bor"?
Bava Kama, 3b: To teach us that one is only Chayav to pay for an animal that falls in and dies 1 if, like a Bor, it is ten Tefachim deep, 2 but if it is only nine Tefachim deep, he is Chayav for damages 3 but not for Misah.
On what basis is the owner of the pit liable? How did his pit kill the animal that fell into it?
What are the implicatons of "Venafal Shamah"
Mechilta: The owner is only Chayav if the animal fell by itself, but not if it fell backwards 1 into the oit due to someone who was banging inside it.
See Torah Temimah, note 262, who explains clarifies when the owner is Patur and why, and why the person who is banging is always Patur.
Why is the first "Bor" in the verse written full, and the latter is missing a Vav?
Divrei Eliyahu, Kol Eliyahu, Toras Moshe and Oznayim la'Torah: This hints to what Rashi wrote, that one who opens a pit is liable [if an animal fell in and died] only if it is a full pit [of 10 Tefachim], but if there was already a pit of nine Tefachim, one who digs and completes it to 10 is liable, even though he did not dig a full Shi'ur. 1
Ba'al ha'Turim ha'Aruch: This is the only place "Bor" is written Chaser, for this reason.
QUESTIONS ON RASHI
Rashi writes that "Chamor" teaches that one is exempt if Kelim fall in and break. We should know this already from "Shor", which is equated to Shor of Shabbos. There, Kelim are excluded. One is not commanded that his Kelim rest!
Water is considered like a Kli, that a pit is exempt for damage to it (Bava Kama 48b), and likewise Peros (Aruch ha'Shulchan CM 412:10). We could not learn these from the Gezeirah Shavah to Sinai, for rest does not apply to them. (PF)
Rashi writes that "Shor" teaches that one is exempt if a person falls in and dies. We should know this already from "veha'Mes Yihyeh Lo." One may not benefit from a Mes!
Moshav Zekenim: We need an exclusion for man 1 , and an exclusion for a blemished Korban (the only benefit allowed is to eat the meat, if it was slaughtered).
Da'as Zekenim, Hadar Zekenim #1, Riva #1, based on the Yerushalmi: One may benefit from a dead sLa'ave who circumcised, but did not immerse. ("Shor" exempts a pit for him.) We learn that a Mes is Asur b'Hana'ah from Miryam, i.e. a Yisraelis.
Hadar Zekenim #2, Riva #2: One may benefit from skin of a Mes. 2
Hadar Zekenim citing Ri of Korvil: Had "Shor" not excluded man, we would have expounded "veha'Mes Yihyeh Lo" to teach that the owner [of the ox] deals with the Neveilah (he is paid only the difference between a live animal and the Neveilah). 3
Hadar Zekenim citing R. Varidmus: Had "Shor" not excluded man, we would have expounded "veha'Mes Yihyeh Lo" to exclude man, and not Pesulei ha'Mukdashim, for skin of the latter is permitted. 4
Riva #2: Had "Shor" not excluded man, we would have expounded "veha'Mes Yihyeh Lo" to exclude man, whose corpse is never "Lo", and not Shor, for sometimes its Neveilah is permitted (i.e. Chulin).
Riva #3: We cannot exclude man from "veha'Mes Yihyeh Lo", for if so, also an ox would not pay for goring man (verse 36), but the Torah explicitly taught Kofer in this case!
Riva citing Ri of Korvil: If not for Shor, we would have excluded only man, for he should look where he walks, but one would pay for Kelim.
Moshav Zekenim: Do not say that one may benefit from his hair. Also Pesulei ha'Mukdashim, one may benefit from the hair, and "veha'Mes Yihyeh Lo" excludes them!
Riva: We learn that a Mes is Asur b'Hana'ah from Kodshim. The skin of Kodshim is permitted!
Hadar Zekenim elaborates how we would have expounded without "Shor", and how we expound now that it was written.
Rashi writes that "Shor" exempts for a person, and "Chamor" exempts for Kelim. We need one of these for a Gezeirah Shavah to Shabbos to include all animals. Only one of them is extra to exclude people or Kelim!
Da'as Zekenim, Hadar Zekenim: The Torah could have written only "v'Nafal", and we would include everything. Therefore, we must say that both "Shor" and "Chamor" are expounded [to exclude].
Riva: Shor of Shabbos is not needed for any Drashah. If a Gezeirah Shavah is free from one side, all agree that we learn if there is no challenge to it.
Perhaps "Chamor" is used for the Gezeirah Shavah to Shabbos, and this excludes Kelim, for one is not commanded that his Kelim rest! (PF) Refer to question 21:33:151.
Rashi writes that if one is liable for exposing a pit, all the more so one is liable for digging one. The Torah needed to write digging, to exempt for people and Kelim even in this case!
Riva: Had the Torah wrote only about exposing, we would have no source to be more stringent about digging, and obligate for people and Kelim.
Rashi writes that "Chamor" exempts for Kelim. We should know this, for Kelim do not fall by themselves, only if someone threw them in!
Riva citing R. Efrayim: We cannot collect from the one who caused them to fall, for it was amidst Ones, so we collect from the owner of the pit. 1
Riva citing Tuch: We need to exempt Kelim that the wind blew them into a pit.
Riva: This is wrong. Only R. Nasan says so, but Chachamim disagree!