For I testify again to every man that is circumcised, that he is a debtor to do the whole law.
All Commentaries on Galatians 5:3 Go To Galatians 5
Ambrosiaster
AD 400
There are some who serve the law to a certain extent without being circumcised; for many Romans in Judea served the law without circumcision. … Yet there is no one who is circumcised without being required to serve the whole law. He is a debtor, since the law was given to the circumcised. His meaning here was that they had become so negligent as to deserve to bear all the burdens of the law.