Romans 2:28-29

You are not a true Jew if you are only a Jew in your physical body. True circumcision is not only on the outside of the body. A true Jew is one who is a Jew inside. True circumcision is done in the heart. It is done by the Spirit, not by the written law. And anyone who is circumcised in the heart by the Spirit gets praise from God, not from people.