Genesis 21:2-5

Brenton(i) 2 And she conceived and bore to Abraam a son in old age, at the set time according as the Lord spoke to him. 3 And Abraam called the name of his son that was born to him, whom Sarrha bore to him, Isaac. 4 And Abraam circumcised Isaac on the eighth day, as God commanded him. 5 And Abraam was a hundred years old when Isaac his son was born to him.