What is the meaning of "ve'His'halech ba'Chutz alMish'anto"?
Rashi and Targum Onkelos: It means that he has regained his full strength. 1
Ramban #1 and Targum Yonasan: It means that he is able to leave his house leaning on his cane. 2
Ramban #2 (citing the Mechilta): It is only if the victim is well enough to go outside - albeit leaning on his cane, 3 that the culprit is Patur even if he (the victim) subsequently dies. The fact that he is able to walk around the house is no indication that he has recovered.
Moshav Zekenim: He can walk well. This is a metaphor, like "Im Zarchah ha'Shemesh ALa'av", and "u'Farsu ha'Simlah
See Sifsei Chachamim. Ramban, citing the Ibn Ezra, explains that he is leaning on his own body and not on someone else's.
Our version of the Mechilta however, translates "al Mish'anto' as 'fully recovered.
Why does the Torah add the words "Im Yakum"?
Oznayim la'Torah: To teach us that Reuven is only Patur if Shimon was able to get up unaided and walk outside, but not if he needed help. 1
Why does the Torah need to insert the words "Venikah ha'Makeh"? Is it not obvious that if Shimon recovers, Reuven is not sentenced to death?
Rashi: Ot teaches us that, if Shimon does not die immediately, Reuven is incarserated until he recovers, and only then is he let off the hook.
Why does the Torah use the double Lashon "ve'Rapo Yerapei"?
Bava Kama 85a: To teach us that even when he is Chayav Nezek, he is Chayav Ripuy as well. 1
Bava Kama 85a: This teaches that doctors are allowed to heal.
Moshav Zekenim #1: Even though the assailant is a doctor, the victim can say 'you seem like a Rasha to me; hire another doctor!'
Moshav Zekenim #2: If one doctor cannot heal him, he may go to another. Do not say that Hashem does not want to heal him.
Targum Yonasan: He is obligated to pay for medical expenses until the wound is fully healed.
What is the time limit for letting the accused off the hook?
Rashbam: There is no time limit; even if the victim dies from his wounds muchlater, the culprit is Chayav Misah 1 (provided the victim did not leave his house before the woundhealed).
As opposed to one's Eved Cana'ani, which the Torah will discuss in the next Pasuk (Rashbam).
Why does the Torah not simply write "Shivto u'Refu'aso Yiten"?
Ramban: To teach us that the culprit is obligated to pay the doctor's fees, and that the victim cannot take the money and use it for other things.
What is "Rak" coming to preclude?
Bava Kama, 88a: To exempt Reuven from paying for cures resulting from Shimon ignoring doctor's orders and eating sweet things that are bad for the wound. -
Why does the Torah use the double expression "Verapo Yerapei"?
Bava Kama, 88a: To teach us that Reuven is obligated to pay even for a growth that subsequently appears on the wound. 1
Bava Kama, 88b: To permit a doctor to cure. 2
Bava Kama, 88b: To obligate Reuven to pay Ripuy even if he has to pay Nezek as well.
See Torah Temimah, note 164.
And it is not considered negating Hashem's decrees. R. Bachye confines this concession to external wounds, but prohibits a doctor from treating internal ailments. See Oznayim la'Torah DH "ve'Rapo Yerapei #3, who proves that the Torah's concession incorporates internal wounds as well. See also Oznayim la'Torah DH #4.
Bava Kama 85a learns from "v'Rapo Yerapei" that doctors may heal. We should know this already from "va'Hashevoso Lo", to include Aveidas Gufo!
Hadar Zekenim (17): "Va'Hashevoso Lo" teaches only when he is drowning, and his body will be lost at once.
Moshav Zekenim: We need our verse to teach that a doctor may receive wages for healing. 1
Moshav Zekenim citing Ri: Our verse permits healing maladies due to man. "Va'Hashevoso Lo" permits healing illnesses from Shamayim.
Moshav Zekenim: Refer to 21:19:2:4.
What is the source? Perhaps the verse obligates only for the medicines! (PF)
Bava Kama 85a learns from "v'Rapo Yerapei" that doctors may heal. We should know this already from "Ki Yazid", which excludes a doctor [who tried to heal, and killed]!
Moshav Zekenim: The verse exempts him, for he was Shogeg, but does not show that l'Chatchilah he may try to heal. 1
The question is not clear to me. If doctors may not heal, we would exclude from "Ki Yazid" only others, e.g. a Shali'ach Beis Din! (PF) Divrei Eliyahu - the Gra remarked that doctors may heal, but there is no source for doctors to say 'there is no Refu'ah'!
Bava Kama 85a learns from "v'Rapo Yerapei" that doctors may heal. Why would I think that they may not? .
Rashi (in Bava Kama 85a): One might have thought that doctors may not heal what Hashem struck. 1
Moshav Zekenim citing R. Chaim: Perhaps the doctor will kill the patient through a potion.
Moshav Zekenim: This cannot be, for it says "Lo Sa'amod Al Dam Re'echa"!
What does "Rak" exclude?
Moshav Zekenim: If the victim transgressed the doctor's words, the assailant need not pay for Refu'ah after this.
QUESTIONS ON RASHI
Rashi writes that "v'Nikah ha'Makeh" teaches that we incarcerate him, and if the victim dies, we kill him. Perhaps the wind confounded him (he did not die due to the blow- Gitin 70b)!
Moshav Zekenim #1: We are concerned for this only regarding one whose Simanei Shechitah were cut.
Moshav Zekenim #2: The verse discusses one in a marble house (there is no wind).
Moshav Zekenim #3: We are concerned for this only regarding Galus.
Moshav Zekenim #4: It was a great wound that cannot heal. 1 Then, there is no concern for wind.
The verse discusses the possibility that he will recover! (PF)