Why does the Torah juxtapose "u'va'Yom ha'Shemini Yimol", to the Din of Tum'as Leidah, implying that the Mitzvah of Milah is connected to Tum'as Leidah?
Shabbos, 135a: To confine the Din of Milah on the eighth day to where the mother is Tamei Leidah. Wherever she is not, 1 the baby must be circumcised as soon as he is fit.
Nidah, 24b: To teach us that if the baby's limbs and head are not properly formed, in which case it is not fit to have B'ris Milah on the eighth day, the mother is not Tamei'ah Leidah.
Such as a Yotzei Dofen or where a Nochris converts a day after giving birth. See Torah Temimah, note 15.
Why does the the (otherwise superfluous) word ?u?va?Yom ha?Shemini?
See Torah Temimah, note 14.
Having already taught us the Din of Milah on the eighth day in Lech-L'cha, 17:12, why does the Torah repeat it here?
Shabbos, 132a: To teach us that the Mitzvah of Milah on the eighth day - both bi'Zemano and she'Lo bi'Zemano - overrides Shabbos. 1
Targum Yonasan: To teach us that the reason that the boy is circumcised on the eighth day is because that is when his mother Tovels and becomes Tahor and is permitted to his father 2 (in which case his father and mother are able to rejoice together with all the participants - Nidah, 31b). 3
Shabbos (Ibid.): "u'va'Yom" - 'Afilu be'Shabbos'!
Peirush Yonasan: Before that, it would be insensitive for everybody else to rejoice over the Mitzvah - whilst the boy's parents are sad. See also Torah Temimah, note #21, who elaborates.
Nevertheless, the Torah fixed the B'ris for the eighth day even when she cannot become Tehorah, such as a Yoledes be'Zov, or if a twin girl was born with the boy? (PF)
Why is B'ris Milah performed specifically on the eighth day?
Targum Yonasan, Hadar Zekenim #1 and Moshav Zekenim (citing Nidah, 31b): Refer to 12:3:1:1.
Seforno: Because that is when the blood of Nidus from which the fetus was fed has been obsorbed, and the baby is Tahor and can enter the B'ris be'Taharah.
When on the eighth day, is the correct time to perform the Mitzvah of Milah?
To whom is the Torah speaking?
Yerushalmi Kidushin, 1:7: It is speaking to the baby's father, placing upon him the Mitzvah of circumcising his son. 1
See Torah Temimah, who, after the citing the Bavli's source for the Mitzvah, explains the Machlokes.
Why does the Torah add the extra 'Vav' and 'Hey' in "u'va'Yom ha'Shemini Yimol"?
Why does the Torah insert the (otherwise superfluous) word "B'sar Orlaso"?
Shabbos, 132b: To teach us that the Mitzvah of B'ris Milah overrides Tzara'as. 1
See Torah Temimah, note 27. See also Oznayim la'Torah who elaborates.
Why does the Torah write "Yimol B'sar Orlaso" and not "Yimol Besaro"?
Shabbos, 132b: To reach us that only a Vaday Orlah overrides Shabbos. but not a Safek (whether it is a seventh or eighth-month baby 1 ), an Androginus, one who is born Bein-ha'Shemashos (at dusk, when it is not certain which day it is) and not on a baby who is born already circumcised, who requires Hatafas Dam B'ris (drawing blood).
Who cannot survive.
If Hashem wants us to be circumcised, why is a boy not born circumcised?
Moshav Zekenim: R. Akiva answered Turnusrufus - that Hashem gave us Mitzvos to purify us and receive reward.
In Shabbos (132b), we learn that B'ris Milah overrides Shabbos. But we already know this from a Kal va'Chomer (since Milah overrides Avodah, and Avodah overrides Shabbos)?
Moshav Zekenim: The Kal v'Chomer can be challenged. Only Korbanos Tzibur override Shabbos, whereas Milah is [like] a Korban Yachid.
Why do we need "u'va'Yom [ha'Shemini]"to teach us that Milah overrides Shabbos (Shabbos 132b)? Even if it was not a Mitzvah, it is mere cutting flesh, like the Gemara states - in Shabbos 136a in connection with a baby born Bein ha'Shemashos?
Moshav Zekenim #1 (citing R. Simchah): The Pasuk excludes an Androginus and someone born circumcised. Such Safek Milah does not override Shabbos. Ba'Yom excludes the [eighth] night. The prefix Vov teaches that even after eight days [Milah must be during the day]. However, why don't we know this already from "u'Ven Shemonas Yamim Yimol" (Bereishis 17:12)?
Moshav Zekenim #2: The Pasuk teaches that the entire day is Kosher for Milah; just zealous people do it promptly. However, Pesachim 4a teaches [that one must] to do it in the morning! 1
Shabbos 136a: It is not needed to permit Milah of a baby born Bein ha'Shemashos; in any case it is permitted. 2 It is needed according to R. Yehudah, who permits Melachah for Machshirei (things needed to enable) Milah. They are permitted only for a Vadai Mitzvah.
It is not clear what his question is. Ba'Yom teaches that the Mitzvah applies the entire day, just Zerizim do it in the morning! (PF)
The Gemara said so about a Safek Nefel! If it is Chai, fine (he properly circumcises). If not (rather, it is a Nefel), he merely cuts flesh. How did Moshav Zekenim understand this to discuss a baby born Bein ha'Shemashos?! Perhaps in his text, the 'Yud' in 'Chai' looked like ' (an apostrophe). His text read 'if it is Ches' (the eighth day), fine. If not, he merely cuts flesh.' This is difficult if birth was when Shabbos entered; if next Shabbos is really day nine, would we call Milah 'mere cutting flesh'?! Rather, birth was when Shabbos ended; if next Shabbos is day seven, there is no Mitzvah, and he merely cuts flesh. Why is this called 'mere cutting'? Due to this, he loses the Mitzvah of Milah tomorrow! Perhaps he holds that Hatafas Dam Bris is as great as Mitzvas Milah. Or, indeed, he loses the Mitzvah; regarding laws of Shabbos, it is mere cutting flesh. (PF)
Why does the Torah add "Yimol B'sar Orlaso"?
Shabbos, 132b: To teach us that Milah - both bi'Zemano and she'Lo bi'Zemano - overrides the La'av of removing Tzara'as - by which the Torah also writes in 13:2 "Adam ki Yih'yeh be'Or Besaro ... ".
What is the reason for B'ris Milah?
Moshav Zekenim (citing the Rambam in Moreh Nevuchim 3:49): To curb excess lust and diminish the amount that one will engage in Bi'ah.
Moshav Zekenim #1: It is a sign that one believes that Hashem is one. A person might want to pretend that he believes, in order to obtain some benefit, but he would not circumcise himself or his son for that.
Moshav Zekenim #2: Because there is great love and freindship among people with the same sign.
