'Servant girl' in the Bible

For it is written that Abraham had two sons, one from the servant girl, and one from the freewoman.

But in fact, the man from the servant girl was born according to flesh, but the man from the freewoman through promise.

Nevertheless, what does the scripture say? Send away the servant girl and her son, for the son of the servant girl will, no, not inherit with the son of the freewoman.

So then, brothers, we are not children of a servant girl, but of the freewoman.