These people who have been instructing you are devoted to you, but not in a good way. They want you to avoid me so that you will be devoted to them.

This is being said as an allegory, for these women represent two covenants. The one woman, Hagar, is from Mount Sinai, and her children are born into slavery.

Look at how large these letters are because I am writing with my own hand!

These people who want to impress others by their external appearance are trying to force you to be circumcised, simply to avoid being persecuted for the cross of the Messiah.