Genesis 21:4 in the King James Version
And Abraham circumcised his son Isaac being eight days old, as God had commanded him.
Context
3 Abraham called his son who was born to him, whom Sarah bore to him, Isaac.
4 Abraham circumcised his son, Isaac, when he was eight days old, as God had commanded him.
5 Abraham was one hundred years old when his son, Isaac, was born to him.