Thematic Bible: Concubines might be dismissed

And Sarah saw the son of Hagar the Egyptian (whom she had borne to Abraham) mocking. And she said to Abraham, Cast out this slave woman and her son. For the son of this slave woman shall not be heir with my son, with Isaac. And the thing was very evil in Abraham's sight, because of his son. read more.
And God said to Abraham, Let it not be grievous in your sight because of the boy and because of your slave woman. In all that Sarah has said to you, listen to her voice. For in Isaac your Seed shall be called. And also, I will make a nation of the son of the slave woman, because he is your seed. And Abraham rose up early in the morning, and took bread and a bottle of water, and gave it to Hagar, putting it on her shoulder. And he gave her the boy, and sent her away. And she departed and wandered in the wilderness of Beer-sheba.