4:21. Tell me, you that desire to be under the law, have you not read the law?
4:22. For it is written that Abraham had two sons: the one by a bondwoman and the other by a free woman.
4:23. But he who was of the bondwoman was born according to the flesh: but he of the free woman was by promise.
4:24. Which things are said by an allegory. For these are the two testaments. The one from Mount Sina, engendering unto bondage, which is Agar.
4:25. For Sina is a mountain in Arabia, which hath affinity to that Jerusalem which now is: and is in bondage with her children.
4:26. But that Jerusalem which is above is free: which is our mother.
4:27. For it is written: Rejoice, thou barren, that bearest not: break forth and cry thou that travailest not: for many are the children of the desolate, more than of her that hath a husband.
4:28. Now we, brethren, as Isaac was, are the children of promise.
4:29. But as then he that was born according to the flesh persecuted him that was after the spirit: so also it is now.
4:30. But 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 free woman.