Layman's Challenge to Galatians

What is the overriding issue within the book of Galatians? It appears that there are three issues going on during this time of Paul being in Galatia.

Is it that the Galatian converts are free from the Law of Moses,

Or is it that Christian converts are not subject to the Abrahamic Covenant and therefore are not required to be circumcised,

Or is it because there are Christian-Jews that want them to b...