Leviticus 12:3 – And on the eighth day, the flesh of his foreskin shall be circumcised.
Gemora Niddah 31b: And why did the Torah ordain circumcision on the eighth day? In order that the guests shall not enjoy themselves while his father and mother are not in the mood for festivities [Lit., ‘sad’, on account of the prohibition of intercourse which remains in force until the conclusion of the seventh day.]
Torah Temimah Colloquial Translation on Note #22:
Rashi explains that everyone would be eating and drinking at the meal, but the father and mother would be sad on account of the prohibition of intercourse. The explanation of this matter is according what we explain shortly that all the blood that a woman sees [soon after] the seventh day would be pure blood and she would be permitted to her husband [from the seventh day on].
It is already well knows the [famous] statement of the Vilna Gaon who uses this point to demonstrate that any [rabbinic] decree that has been made for a particular reason will continue to remain in force even if the reason is no longer in force. In this example here, where it gives one of the reasons for having the circumcision on the eighth day be related to the prohibition on intercourse. However, in our day this reason is no longer applicable [because of the rabbinic degree of waiting an additional 7 days after clean blood]. This being the case, the reason for have the circumcision on the eighth day no longer applies, but nevertheless the law still stands.
Perhaps one can say that this general principle is alluded to in the Tanchuma at the beginning of Parshat Tetzaveh. There, the rabbis ask why the circumcision is on the eighth day. The answer given in the Tanchuma is that the circumcision is on the eighth day because that is when Yitzchak was circumcised. Apparently, neither the question nor the response in the Tanchuma makes sense. Behold, the commandment to do the circumcision on the eighth day is a well known, explicit commandment clearly stated in the Torah itself. Additionally, the time for Yitzchak’s circumcision is also well known and clearly stated. [So, how does the question and the answer of the Tanchuma actually teach us anything that we didn’t already know?]
But according to the Aggadic text of the Gemora Niddah quoted above, [perhaps] we can understand better the text of the Tanchuma and why it is asking about at what age a child should be circumcised in our day. Since the Tanchuma was aware that the reason given for waiting for the eighth day no longer applies, it instead responds that another reason exists that in still in force, namely basing it on when Yitzchak was circumcised. This is especially true since in the time of Yitzchak, prior to the giving of the Torah, there were no laws of Niddah. Therefore, it wasn’t even applicable to wait till the eighth day for the reason given in our Gemora. Nevertheless, they waited till the eighth day anyway for Yitzchak’s circumcision and that is why we also wait till the eighth day.
We should also be aware that the Rambam in his book, Guide for the Perplexed (Chapter 49, Section 2), writes that the reason why the circumcision is done on the eighth day is in order to give the baby’s strength time to grow after the birth. It is an amazing question for the Rambam why he left out mentioning what is written in the Gemora and instead wrote something based on his own logic. [However, we need to keep in mind], that actually the Rambam did not actually originate this idea. Look in the Midrash Rabbah at the beginning of the Parshat Ki Tetzei where it says as follows: “Why is the baby circumcised on the eighth day? Because God had mercy on him and gave time for his strength to grow [after the birth.]” Now you might ask why the Rambam chose this reason to record rather than the reason given in the Gemora, the answer is probably [exactly] because the reason given in the Gemora Niddah cited above is because that reason is no longer applicable due to our observance of the extra stringency of “clean blood”.
Even the reason of the Tanchuma requires further thought. Who set the timeframe of eight days as being sufficient for the baby to gather enough strength for the circumcision? Don’t we find that for an animal we wait seven days to declare him to be in a presumed state of good health while for a person we wait thirty days? This is explained explicitly in the Gemora Shabbos 131b. Perhaps in an aggadic manner one can say that the answer is because in waiting eight days, one is assured that at least one day of Shabbos will occur. Further, as is explained in [various] aggadas, Shabbos has the ability to increase a person’s strength and fortify his nature. This is also explained in other aggadas that before Shabbos was created the world was weak and shuddering, but when Shabbos came the world became strong.
[Parenthetically] keep in mind that we see from the fact that Rashi comments on our Gemora that everyone will be eating and drinking, we see a bit of a source for the obligation to have a festive meal to celebrate the circumcision. This is also alluded to in the Torah itself. The Gemora notes this when it uses the phrase “why does the Torah command the circumcision on the eighth day”. We also have further comments on this issue in Parshat Vaera on the posuk “on the day that Yitzchak was weaned”. Check out my note there.
Editor’s note: I think it is wonderful that the rabbis in the Gemora ask why the Torah commands that a circumcision be done on the eighth day rather than just saying we have to do it because “it says so”. I believe the Torah Temimah is authentically continuing the wonderful Jewish tradition of questioning and challenging everything, even great previous authorities such as the Rambam.