Galatians 4:22-26

For it is written, that Abraham had two sons, the one by a bondmaid, the other by a freewoman.

But he [who was] of the bondwoman was born after the flesh; but he of the freewoman [was] by promise.

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

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

But Jerusalem which is above is free, which is the mother of us all.