'Eight' in the Bible

Throughout your generations every male among you who is eight days old must be circumcised, whether born in your house or bought with money from any foreigner who is not one of your descendants.

When his son Isaac was eight days old, Abraham circumcised him just as God had commanded him to do.

(Now Bethuel became the father of Rebekah.) These were the eight sons Milcah bore to Abraham's brother Nahor.