Worried Parents

The Gemara in מסכת נדה, gives an unclear explanation as to why a the Brit of a Jewish boy is on the eighth day.

The intent was for all present at this ceremony to be in a state of joy, but if not for the eighth day, the new parents of the baby would be sad. There is little explanation for this puzzling statement.

Rav Shlomo Mann זצ״ל, gave a fascinating answer as to the intent of the Gemara. He felt that parents may suddenly be struck with great worries after the birth of their new baby. How will they give him a proper Jewish education. How will they be able to adequately provide for him, and would he one day marry a nice Jewish girl.
In order to put these worries to rest, the Torah ordained that one Shabbat must pass, before the baby is circumcised. When the holy Sabbath comes, all worries are put to rest. A person is to enter this day feeling as if all of his work is done.

When Shabbat comes in, we are reminded that we are a people that defy nature. Our relying on Hashem, is all that is necessary for us. We know that such faith can carry us through all difficulties.

This awareness that Shabbat gives us, brings us great joy. We now have the strength to meet any challenge; including raising a little boy to adulthood. This was what the Gemara meant when it said the Brit had to be on the eighth day. Otherwise, they would have been full of sadness and worry. Their Shabbat experience, set them on the right path. Now they were ready to celebrate the miracle and blessing of bringing their son into the covenant of Abraham.