Formerly when you did not know God, you were enslaved to beings that by nature are not gods at all. ¹ 

But now that you have come to know God (or rather to be known by God), how can you turn back again to the weak and worthless ¹  basic forces? ²  Do you want to be enslaved to them all over again? ³ 

Now Hagar represents Mount Sinai in Arabia and corresponds to the present Jerusalem, for she is in slavery with her children.

For you were called to freedom, brothers and sisters; ¹  only do not use your freedom as an opportunity to indulge your flesh, ²  but through love serve one another. ³