Galatians 4:22-26

22For it is written that Abraham had two sons; one of the maid servant, and one of the free woman.

23But he [that was] of the maid servant was born according to flesh, and he [that was] of the free woman through the promise.

24Which things have an allegorical sense; for these are two covenants: one from mount Sinai, gendering to bondage, which is Hagar.

25For Hagar is mount Sinai in Arabia, and corresponds to Jerusalem which [is] now, for she is in bondage with her children;

26but the Jerusalem above is free, which is our mother.