Galatians 4:22-25

4:22 For it is written that Abraham had two sons, one by the slave woman and the other by the free woman. 4:23 But one, the son by the slave woman, was born by natural descent, while the other, the son by the free woman, was born through the promise. 4:24 These things may be treated as an allegory, for these women represent two covenants. One is from Mount Sinai bearing children for slavery; this is Hagar. 4:25 Now Hagar represents Mount Sinai in Arabia and corresponds to the present Jerusalem, for she is in slavery with her children.