Suppose you call yourself a Jew. You trust in the law. You brag that you are close to God.
References for Romans 2:17
You know what God wants. You agree with what is best because the law teaches you.
You are sure you can lead people who are blind. You are sure you are a light for those who are in the dark.
You claim to be able to teach foolish people. You can even teach babies. You think that in the law you have all knowledge and truth.
You teach others. But you don't teach yourself! You preach against stealing. But you steal!
You say that people should not commit adultery. But you commit adultery! You hate statues of gods. But you rob temples!
You brag about the law. But when you break it, you rob God of his honor!
It is written, "Those who aren't Jews say evil things against God's name because of you."(Isaiah 52:5; Ezekiel 36:22)
Circumcision has value if you obey the law. But if you break the law, it is just as if you hadn't been circumcised.
Sometimes those who aren't circumcised do what the law requires. Won't God accept them as if they had been circumcised?
Many are not circumcised physically, but they obey the law. They will prove that you are guilty. You are breaking the law, even though you have the written law and are circumcised.
A man is not a Jew if he is a Jew only on the outside. And circumcision is more than just something done to the outside of a man's body.
No, a man is a Jew only if he is a Jew on the inside. And true circumcision means that the heart has been circumcised. It is done by the Holy Spirit. It is more than just obeying the written Law. Then a man's praise will not come from others. It will come from God.