Genesis 21:3-5

Wycliffe Bible

³ And Abraham called the name of his son, whom Sarah childed to him, Isaac.

⁴ And Abraham circumcised him in the eighth day, as God commanded to him, (And Abraham circumcised him on the eighth day, as God had commanded to him,)

⁵ when he was of an hundred years; for Isaac was born in this age of the father. (when he was a hundred years old; for this was the age of his father when Isaac was born.)