Galatians 4:27-31

27For it is written: “Rejoice, O barren, You who do not bear! Break forth and shout, You who are not in labor! For the desolate has many more children Than she who has a husband.”

28Now we, brethren, as Isaac was, are children of promise.

29But, as he who was born according to the flesh then persecuted him who was born according to the Spirit, even so it is now.

30Nevertheless what does the Scripture say? “Cast out the bondwoman and her son, for the son of the bondwoman shall not be heir with the son of the freewoman.”

31So then, brethren, we are not children of the bondwoman but of the free.