Genesis 21:7-11
English Standard Version
8And the child grew and was weaned. And Abraham made a great feast on the day that Isaac was weaned.
9But Sarah saw the son of Hagar the Egyptian, whom she had borne to Abraham, laughing.
10So she said to Abraham, "Cast out this slave woman with her son, for the son of this slave woman shall not be heir with my son Isaac."
11And the thing was very displeasing to Abraham on account of his son.