Wherefore she said unto Abraham, Cast out this bondwoman and her son: for the son of this bondwoman shall not be heir with my son, [even] with Isaac. (21:10)

And the thing was very grievous in Abraham's sight because of his son. (21:11)

And God said unto Abraham, Let it not be grievous in thy sight because of the lad, and because of thy bondwoman; in all that Sarah hath said unto thee, hearken unto her voice; for in Isaac shall thy seed be called. (21:12)

And also of the son of the bondwoman will I make a nation, because he [is] thy seed. (21:13)

And Abraham rose up early in the morning, and took bread, and a bottle of water, and gave [it] unto Hagar, putting [it] on her shoulder, and the child, and sent her away: and she departed, and wandered in the wilderness of Beersheba. (21:14)

--Galations--

For it is written, that Abraham had two sons, the one by a bondmaid, the other by a freewoman. (4:22)

But he [who was] of the bondwoman was born after the flesh; but he of the freewoman [was] by promise. (4:23)

Which things are an allegory: for these are the two covenants; the one from the mount Sinai, which gendereth to bondage, which is Agar. (4:24)

For this Agar is mount Sinai in Arabia, and answereth to Jerusalem which now is, and is in bondage with her children. (4:25)

But Jerusalem which is above is free, which is the mother of us all. (4:26)

For it is written, Rejoice, [thou] barren that bearest not; break forth and cry, thou that travailest not: for the desolate hath many more children than she which hath an husband. (4:27)

Now we, brethren, as Isaac was, are the children of promise. (4:28)

But as then he that was born after the flesh persecuted him [that was born] after the Spirit, even so [it is] now. (4:29)

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. (4:30)