'Freewoman' in the Bible

For it is written that Abraham had two sons, one by the slave woman [Hagar] and one by the free woman [Sarah].

But the child of the slave woman was born according to the flesh and had an ordinary birth, while the son of the free woman was born in fulfillment of the promise.

But what does the Scripture say?“Cast out the bondwoman [Hagar] and her son [Ishmael],For never shall the son of the bondwoman be heir and share the inheritance with the son of the free woman.”