Luke 1:59
and on the eighth day were present at the circumcision of the child. but upon their proposing to call him by his father's name, Zacharias: his mother objected to it,
Luke 2:21
The eighth day, when the child was to be circumcised, being come, he was named Jesus, the name, which the angel had given before his conception.
Philippians 3:5
being circumcised the eighth day, of the family of Israel, of the tribe of Benjamin, an Hebrew by descent, by sect a Pharisee.
Acts 7:8
at length he gave him the covenant of circumcision: accordingly Abraham circumcised his son Isaac eight days after he was born, Isaac was father of Jacob, who was father of the twelve patriarchs.