Romans 2:25-28

For indeed circumcision is of value if you practice the Law; but if you are a transgressor of the Law, your circumcision has become uncircumcision. So if the uncircumcised man keeps the requirements of the Law, will not his uncircumcision be regarded as circumcision? And he who is physically uncircumcised, if he keeps the Law, will he not judge you who though having the letter of the Law and circumcision are a transgressor of the Law? For he is not a Jew who is one outwardly, nor is circumcision that which is outward in the flesh.