Genesis 21:9-12

And Sarah saw the son of Hagar the Egyptian, whom she had borne to Abraham, scoffing. Therefore she said to Abraham, “Cast out this bondwoman and her son; for the son of this bondwoman shall not be heir with my son, namely with Isaac.” And the matter was very displeasing in Abraham’s sight because of his son. But God said to Abraham, “Do not let it be displeasing in your sight because of the lad or because of your bondwoman. Whatever Sarah has said to you, listen to her voice; for in Isaac your seed shall be called.