“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.”
King James Version (KJV)
4:30 But what saith the scripture - Showing the consequence of this. Cast out the bondwoman and her son - Who mocked Isaac. In like manner will God cast out all who seek to be justified by the law; especially if they persecute them who are his children by faith. #Gen 21:10|.
Ga 4:30 What saith the scripture? See Ge 21:10. Cast out the bondwoman and her son. The allegory will hold good still further. Abraham, when it was impossible that the two families should get along in peace, cast out the bondwoman and her son. For the son of the bondwoman shall not be heir with the son of the freewoman. So, too, the Jews, the children of the old covenant, had lost the divine favor, and the children of the promise, whether Jews or Gentiles, made heirs.