Genesis 21
9 Ref And Sarah saw the son of Hagar the Egyptian playing with Isaac.
10 Ref So she said to Abraham, Send away that woman and her son: for the son of that woman is not to have a part in the heritage with my son Isaac.
11 Ref And this was a great grief to Abraham because of his son.
12 Ref But God said, Let it not be a grief to you because of the boy and Hagar his mother; give ear to whatever Sarah says to you, because it is from Isaac that your seed will take its name.
13 Ref And I will make a nation of the son of your servant-woman, because he is your seed.