Genesis 21:6-10

And Sarah said, “God has made me laugh. Everyone who hears about this will laugh with me. No one thought that I would be able to have Abraham’s child, but even though Abraham is old I have given him a son.” Isaac grew, and when he became old enough to eat food, Abraham gave a great feast. But Sarah saw Ishmael making fun of Isaac. (Ishmael was the son of Abraham by Hagar, Sarah’s Egyptian slave.) So Sarah said to Abraham, “Throw out this slave woman and her son. Her son should not inherit anything; my son Isaac should receive it all.”