Hagar and Sarah
Tell me, you who want to be under the law, are you not aware of what the law says? For it is written that Abraham had two sons, one by the slave woman and the other by the free woman. His son by the slave woman was born according to the flesh, but his son by the free woman was born as the result of a divine promise.
These things are being taken figuratively: The women represent two covenants. One covenant is from Mount Sinai and bears children who are to be slaves: This is Hagar. Now Hagar stands for Mount Sinai in Arabia and corresponds to the present city of Jerusalem, because she is in slavery with her children. But the Jerusalem that is above is free, and she is our mother. For it is written:
“Be glad, barren woman,
you who never bore a child;
shout for joy and cry aloud,
you who were never in labor;
because more are the children of the desolate woman
than of her who has a husband.”4:27 Isaiah 54:1
Now you, brothers and sisters, like Isaac, are children of promise. At that time the son born according to the flesh persecuted the son born by the power of the Spirit. It is the same now. But what does Scripture say? “Get rid of the slave woman and her son, for the slave woman’s son will never share in the inheritance with the free woman’s son.”4:30 Gen. 21:10 Therefore, brothers and sisters, we are not children of the slave woman, but of the free woman.
Freedom in Christ
It is for freedom that Christ has set us free. Stand firm, then, and do not let yourselves be burdened again by a yoke of slavery.
Mark my words! I, Paul, tell you that if you let yourselves be circumcised, Christ will be of no value to you at all. Again I declare to every man who lets himself be circumcised that he is obligated to obey the whole law. You who are trying to be justified by the law have been alienated from Christ; you have fallen away from grace. For through the Spirit we eagerly await by faith the righteousness for which we hope. For in Christ Jesus neither circumcision nor uncircumcision has any value. The only thing that counts is faith expressing itself through love.