Galatians 5:3

The false teachers had insisted on the observance of circumcision and a few other rites only, as necessary for salvation; but St. Paul assures them, that the receiving of circumcision is an open profession of Judaism, and that he that makes this profession, binds himself to the observance of every part of the law, since a curse is pronounced against those that do not keep it in all its parts. If then circumcision be necessary for salvation, the whole law is necessary also. (Calmet)