For it is written, that Abraham had two sons, the one by a female slave, the other by a free woman.
And Hagar bore Abram a son: and Abram called his son's name, which Hagar bore, Ishmael.
Why she said to Abraham, Cast out this female slave and her son: for the son of this female slave shall not be heir with my son, even with Isaac.
But he who was of the female slave was born after the flesh; but he of the free woman was by promise.
Nevertheless what said the scripture? Cast out the female slave and her son: for the son of the female slave shall not be heir with the son of the free woman.
So then, brothers, we are not children of the female slave, but of the free.