A child is usually circumcised at eight days, but sometimes he is circumcised at nine, ten, eleven, or twelve days — no earlier or later. How so?
As this mishnah illustrates, there may be legal reasons to delay a child’s circumcision by one to four days. The mishnah is about to explain them, but perhaps you’d like to guess first? Got your guess? Ok, let’s keep reading the mishnah to find the answers:
If he was born at twilight and it is therefore uncertain on which day he was born, he is circumcised at nine days.
In the rabbinic world, where the setting of the sun (and not the stroke of midnight) determines the transition from one day to the next, a baby who is born as the sun sinks below the horizon might have an uncertain birthday. If we don’t know whether he was born at the tail end of Tuesday or in the first moments of Wednesday, the mishnah explains, we circumcise him on Wednesday — which might technically be the ninth day of his life.
Ready for the answer about ten days? Here’s a clue: we’re in tractate Shabbat, so that’s going to factor in to the answer. And even though circumcision overrides Shabbat (as we recently learned), Shabbat can still interfere with certain circumcisions. Ready to find out how?
If he was born at twilight on Shabbat eve, he is circumcised at ten days.
This baby was not born midweek at sundown, but just as Shabbat was coming in. It is not known if he was born on Erev Shabbat or Shabbat itself. According to the principle articulated above, we would ordinarily be inclined to circumcise him on Shabbat which is either the eighth or ninth day of life. But because Shabbat is not certainly the right day for the circumcision, the circumcision cannot override Shabbat and is put off until Sunday — the tenth day.
But why might a circumcision be delayed until the eleventh day of life? Can you guess? Back to the mishnah:
If there was a festival after that Shabbat, he is circumcised at eleven days.
If the baby boy was born at twilight as Shabbat was coming in and Sunday happened to be a chag, a festival day, then his circumcision would also be delayed out of deference to that festival.
So that leaves only the twelve day delay to explain:
And if that Shabbat was followed by two days of Rosh Hashanah, he is circumcised at twelve days.
And, for good measure, the mishnah then notes that if a child is too ill to undergo the procedure, one of course waits until he is healthy — as long as that takes. This is the only part of the mishnah that is picked up for discussion in the Gemara. The rest is, apparently, self-explanatory.