Galatians 4:22
For it is written, that Abraham had two sons, the one by a bondmaid, the other by a freewoman.
Galatians 4:23
But he who was of the bondwoman was born after the flesh; but he of the freewoman was by promise.
Galatians 4:30
Nevertheless what saith the scripture? Cast out the bondwoman and her son: for the son of the bondwoman shall not be heir with the son of the freewoman.