And Jehovah visited Sarah as he had said, and Jehovah did to Sarah as he had spoken.
And Sarah conceived, and bore Abraham a son in his old age, at the appointed time of which God had spoken to him.
And Abraham called the name of his son who was born to him, whom Sarah bore to him, Isaac.
References for Genesis 21:3
And Abraham circumcised his son Isaac, being eight days old, as God had commanded him.
And Abraham was a hundred years old when his son Isaac was born to him.
And Sarah said, God has made me laugh: all that hear will laugh with me.
References for Genesis 21:6