These things serve as illustrations, for the women represent two covenants. One covenant is from Mount Sinai and bears children into slavery: This is Hagar.
KJV
Which things are an allegory: for these are the two covenants; the one from the mount Sinai, which gendereth to bondage, which is Agar.
ASV
Which things contain an allegory: for these women are two covenants; one from mount Sinai, bearing children unto bondage, which is Hagar.