Romans 2:17-29 NIV
Now you, if you call yourself a Jew; if you rely on the law and boast in God; if you know his will and approve of what is superior because you are instructed by the law; if you are convinced that you are a guide for the blind, a light for those who are in the dark, an instructor of the foolish, a teacher of little children, because you have in the law the embodiment of knowledge and truth— you, then, who teach others, do you not teach yourself? You who preach against stealing, do you steal? You who say that people should not commit adultery, do you commit adultery? You who abhor idols, do you rob temples? You who boast in the law, do you dishonor God by breaking the law? As it is written: “God’s name is blasphemed among the Gentiles because of you.”
Circumcision has value if you observe the law, but if you break the law, you have become as though you had not been circumcised. So then, if those who are not circumcised keep the law’s requirements, will they not be regarded as though they were circumcised? The one who is not circumcised physically and yet obeys the law will condemn you who, even though you have the written code and circumcision, are a lawbreaker.
A person is not a Jew who is one only outwardly, nor is circumcision merely outward and physical. No, a person is a Jew who is one inwardly; and circumcision is circumcision of the heart, by the Spirit, not by the written code. Such a person’s praise is not from other people, but from God.
NIV: New International Version