“For you are not a true Jew just because you were born of Jewish parents or because you have gone through the ceremony of circumcision. No, a true Jew is one whose heart is right with God. And true circumcision is not merely obeying the letter of the law; rather, it is a change of heart produced by the Spirit. And a person with a changed heart seeks praise from God, not from people.” Romans 2:28-29
Paul tells us that circumcision guarantees nothing. True religion is about a matter of the heart. It is about the inner man, not the outer man. It is not about how we look it is about how we act. To be sure, circumcision was a sign of membership in the covenant community of Israel, but it was only a sign. The true Jew is not one who is merely circumcised outwardly. It is about an inward circumcision of the heart. The circumcision Paul intends here is in keeping with the promise in Jeremiah. “The day is coming,” says the Lord, “when I will make a new covenant with the people of Israel and Judah. This covenant will not be like the one I made with their ancestors when I took them by the hand and brought them out of the land of Egypt. They broke that covenant, though I loved them as a husband loves his wife,” says the Lord. “But this is the new covenant I will make with the people of Israel after those days,” says the Lord. “I will put my instructions deep within them, and I will write them on their hearts. I will be their God, and they will be my people. And they will not need to teach their neighbors, nor will they need to teach their relatives, saying, ‘You should know the Lord.’ For everyone, from the least to the greatest, will know me already,” says the Lord. “And I will forgive their wickedness, and I will never again remember their sins.” (Jeremiah 31:31-34) This promise is to the Jews and the Gentiles. It is the coming of Jesus Christ, Our Lord and Savior. Which if we repent ,will make us right with God.