CIRCUMCISION REFERS TO SOMEONE WHO IS JEWISH

Acts 10:45 And they of the circumcision which believed were astonished as many as came with Peter because that on the Gentiles also was poured out the gift of the Holy Ghost.

Acts 11:2 And when Peter was come up to Jerusalem, they that were of the circumcision contended with him

Romans 3:1 What advantage then has the Jew? or what profit is there of circumcision?