ויקרא פרק יב, ב דַּבֵּר אֶל-בְּנֵּי יִשְּרָאֵּל לֵּאמֹר אִשָה כִי תַּזְּרִ יעַּ וְּיָלְּדָה זָכָר וְּטָמְּאָה שִבְּעַּת יָמִים כִימֵּי נִדַּת דְּ וֹתָהּ תִטְּמָא
תורת כהנים בני ישראל מטמאין בלידה ואין עובדת כוכבים מטמאין בלידה
The Gemara (Shabbos 135a) establishes a general principle: all mothers that becomes tameh during the birth, the male child is given a bris milah at eight days; whereas all mothers that do not become tameh during birth, the child is not given a bris milah at eight days, but upon the day of the birth.
Thus, a non-Jewish mother gives birth (and does not become tameh due to birthing) and then converts, the child is given a bris immediately. And there are other practical differences.
The Eighth Day Overrides Shabbos
ויקרא פרק יב, ג וּבַּיּוֹם הַּשְּמִינִי יִמּוֹל בְּשַּר עָרְּ לָתוֹ :
שבת קל"ב א' ביום ואפילו בשבת
It would have been enough for the verse to say “in the eighth (without the word ‘day’), one should circumcise.” Therefore, the Gemara understands that the addition of the word ביום indicates specifically the day of the eighth, even if it is Shabbos.
In many places the word יום implies a limitation of the day, but not night, perhaps also concerning circumcision the word here might also mean to exclude the night (and not an inclusion of Shabbos). However, an early verse in Lech Lecha limits this mitzvah to day and not night, thus this verse is open for an inclusion to include even on Shabbos.
One should understand that the concept of a circumcision overriding Shabbos applies only to the act itself but not to the preparations (for example, bringing a knife on Shabbos through the Reshus HaRabim). This follows another general principle: all that is possible to do before Shabbos, cannot be done on Shabbos. However, Tosefos (Gittin 7b) states that the principle of circumcision overriding Shabbos does mitigate another principle that what a Jew cannot do (even from a Rabbinical restriction) one cannot ask a non-Jew to do that action (אמירה לנכרי). But in the case of circumcision on Shabbos, one can ask a non-Jew to bring the knife.
One should understand that another general principle does not apply in the case of circumcision on Shabbos, the principle of concern that we forbid a positive mitzvah since the Rabbis were concerned that someone would carry an object four amos on Shabbos (i.e. Shofar, lulav). The principle of permission to do a circumcision on Shabbos (permission from the Torah to override Shabbos) is not subject to the Rabbinical decree to not permit.
Don’t See Negaim on a Chasan or for Yom Tov
ויקרא פרק יג, יד וּבְּיוֹם הֵּרָאוֹת בוֹ בָשָר חַּי יִטְּ מָא:
תורת כהנים יש יום שאתה רואה בו ויש יום שאי אתה רואה בו, חתן נותנים לו שבעת ימי משתה, ברגל נותנים לו שבעת ימי הרגל
Know that the Torah provided the Rabbis the option to select the days that were exempt from seeing. This is the judgment of the Ritva. And this is evident from this statement that a Chasan, from the Torah, has only the one day of the wedding, yet the Rabbis proclaimed the exemption for a seven day period.
ויקרא פרק יב, ג וּבַּיּוֹם הַּשְּמִינִי יִמּוֹל בְּשַּר עָרְּ לָתוֹ :
The Medrash asks why a child waits to the eighth day to be circumcised and answers that this period enables the child to gather strength. The Medrash does not explain the source for this concept.
It is possible to explain from an understanding of the creation of the world. At the time of the creation of the world during the first six days, all the creations were weak and sickly until the arrival of Shabbos, which brought healing and strengthening to all the creations. This is the blessing of Shabbos.
Thus, once eight days have based for any child, then a Shabbos has occurred which enabled a strengthening of the child to allow for the circumcision. The rule was established for all children even those that had a Shabbos earlier than their eighth day.
Why do the circumcision on the eighth day, shouldn’t it be on the seventh day? Seven full units represent the concept of reaching a completeness or maturity. For example, one opinion in halacha is that we wait till after the seventh day to bless the new moon, since only at that point the light reflected by the new moon is complete. Other examples of seven days include the concept of Nidah, Shmitah, Metzora, holidays, days of celebration, days of mourning, etc.
From this verse in VaYikra the Rabbis also learn that circumcision on the eighth day overrides Shabbos. And some ask why don’t the Rabbis make a decree not to do a circumcision on Shabbos, since we might be concerned that someone would carry items needed for the circumcision though the Reshus HaRabim.
We could answer that such a rule was made for Shofar (Rosh HaShana) and lulav (Sukkos) since most people are not experts in the declaration of the first of the month and the fifteenth of the month. Thus, it is possible that the day of Shabbos is not really the time to do the mitzvah of Shofar or Lulav. And due to this confusion it would not be enough for that Mitzvah to override the sanctity of Shabbos.
This reasoning does not apply to the eighth day of a new-born child, since the day of birth is known, and thus, no such reason to apply a decree for concern regarding this type of mitzvah on Shabbos.
Nevertheless, Rabbi Epstein seeks a reason for the concept of circumcision overriding Shabbos. He is not satisfied with the reason that bris milah and Shabbos are both signs, since why would the bris override Shabbos (and not the other way).
Thus, he proposes that a main concept of the bris milah is the foundation that a difference exists between the Jews and the rest of humanity. Non-Jews are not supposed to keep a night and day of Shabbos commands, since after the Flood (Bereshis 8, 14) non-Jews were commanded ויום ולילה לא ישבתו (not to keep a full day of Shabbos). Therefore, the mitzvah of Milah (the first command to the Jewish people) is the initial preparation of a Jew to be obligated in the command of Shabbos. And thus, the earlier mitzvah of Milah would by logic override the mitzvah of Shabbos.
Another matter to discuss: why is a child considered strong enough for the bris milah after seven complete days, but for the Pidyon haBen we wait for 30 days to pass? It is possible to answer that the majority of children are strong enough after seven days. Thus, we go after the majority in most laws of Torah. However, regarding the Pidyon haBen, we are attempting to remove money. In cases of money we do not go after a simple majority, but need a “super” majority that almost all children would be healthy, which only happens after 30 days.
