Genesis 21:9-13

9And Sarah saw the son of Hagar the Egyptian, whom she had borne to Abraham, mocking.

10And she said to Abraham, Cast out this handmaid and her son; for the son of this handmaid shall not inherit with my son — with Isaac.

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

12And 1God said to Abraham, Let it not be grievous in thy sight because of the lad and because of thy handmaid: [in] all that Sarah hath said to thee hearken to her voice, for in Isaac shall a seed be called to thee.

13But also the son of the handmaid will I make a nation, because he is thy seed.