Genesis 21:7

3And Abraham called the name of his son that was born unto him, whom Sarah bare to him, Isaac.

4And Abraham circumcised his son Isaac being eight days old, as God had commanded him.

5And Abraham was an hundred years old, when his son Isaac was born unto him.

6And Sarah said, God hath made me to laugh, so that all that hear will laugh with me.

7And she said, Who would have said unto Abraham, that Sarah should have given children suck? for I have born him a son in his old age.

8And the child grew, and was weaned: and Abraham made a great feast the same day that Isaac was weaned.

9And Sarah saw the son of Hagar the Egyptian, which she had born unto Abraham, mocking.

10Wherefore she said unto Abraham, Cast out this bondwoman and her son: for the son of this bondwoman shall not be heir with my son, even with Isaac.

11And the thing was very grievous in Abraham’s sight because of his son.