The Jewish tradition of Brit Milah, or the circumcision of boys, dates back to Bible times. It is a ceremony where Jewish boys as young as eight years old are circumcised as a remembrance of the covenant of Abraham with God.
In Genesis 17:9-11, “God further said to Abraham, ‘As for you and your offspring to come throughout the ages shall keep My covenant. Such shall be the covenant between Me and you and your offspring to follow which you shall keep: every male among you shall be circumcised. You shall circumcise the flesh of your foreskin and that shall be the sign of the covenant between you and Me.'”
To keep the covenant between Abraham’s descendants, the Israelites, and God, they are to observe circumcision. Traditionally, the brit milah or bris occurs during the eighth day of a Jewish boy’s life. It does not matter whether it may fall on a Shabbat or a Jewish holiday. But, if there are medical concerns, the bris is postponed and scheduled on another day that is not Shabbat or a holiday.
During the bris, a Jewish parent goes to a mohel, a man trained in the Jewish laws to perform circumcision. Sometimes they are physicians, rabbis, cantors, or nurse-midwives. A sandek, the person who will hold the baby during circumcision, is often the baby’s grandparent. Together with the parents, they will perform the ceremony which involves a recitation of blessings and prayers for the infant.
Hebrew name assignment
The bris is also the time when a Hebrew name is given to the baby. Parents will then often explain the reason behind the Hebrew name. A festive meal is then prepared after the ceremony.
Some families observe customs like Shalom Zakhar. It is a festive meal prepared Friday night before the bris and usually attended by 10 adult Jews. They also reserve one chair for the prophet Elijah.
Today, not all Jewish parents practice the traditions involving brit milah. They would rather have their son circumcised in the hospital, with only close family present.
Reference: My Jewish Learning