Niddah 42: When Circumcision is Permitted

Today we learn about brit, circumcision, which is commanded to take place eight days after a child's birth - the same day of the week as the birth itself. The rabbis ask what should be done if a baby is born on the twilight between erev Shabbat and Shabbat.  We learn though the Gemara that it is permitted to perform a circumcision on Shabbat, but if there is a doubt as to when the baby was born, we do not opt for a brit on Shabbat.  Instead, we wait for Sunday or another day for the brit.  Of course, if there are any medical issues, the birt is postponed until the infant is well.