The communion meal would, according to the views of Robertson Smith, also involve the idea of a covenant; while the fact that no person joining in the meal should be uncircumcised connects the feast with the covenant of Abraham.
Formally he was an orthodox Jew and set his face against intermarriage with the uncircumcised.
Other fundamental principles of Paul's failed of comprehension and acceptance, but the belief finally prevailed that the observance of Jewish law and custom was unnecessary, and that in the Christian Church there is no distinction between the circumcised and the uncircumcised.
Then he who is physically uncircumcised but keeps the law will condemn you who have the written code and circumcision but break the law.
If you are circumcised when you were called, don't become uncircumcised, and vise versa.