'Freewoman' in the Bible

For it is written that Abraham had two sons, one by a slave woman and the other by a free woman.

But the heavenly Jerusalem is the free woman, and she is our spiritual mother.

But what does the Scripture say? "Drive out the slave woman and her son, for the son of the slave woman must never share the inheritance with the son of the free woman."

So then, brothers, we are not children of the slave woman but of the free woman.