Genesis 21:9-12

But Sarah noticed the son of Hagar, the Egyptian, was mocking her son Isaac. So she said to Abraham, “Get rid of this slave woman and her son. Banish them, for the son of that slave woman must not become a coheir with my son Isaac!” Abraham was very upset over Sarah’s demand, for Ishmael was his son too. God spoke to Abraham, “Don’t be distressed over the slave woman and her son. Listen to every word Sarah says to you, and do it, for it will be through Isaac your promise of descendants will be fulfilled.