For he is not a Jew who is one outwardly, nor is circumcision that which is outward in the flesh; but he is a Jew who is one inwardly; and circumcision is that of the heart, in the Spirit, not in the letter, whose praise is not from men but from God.
Romans 2:28.29.
Even in Old Testament times God was not satisfied with any mere outward circumcision (cf. Deuteronomy 10:16; Jeremiah 4:4). Solely with the “circumcision of the heart” can one serve God with all one’s heart. And this particular “circumcision” was even then not a work of man’s in his own power, but the work of God (cf. Deuteronomy 30:6).
The apostle mentions the contrast, “of the Spirit” and “of the letter” in 2 Corinthians 3, vv. 6 & 7: “The letter kills, but the Spirit gives life”. Then he shows that the Lord is the Spirit (v.17). The forms and illustrations of the law point to Christ, the coming Redeemer. External forms apart from Him only augment man’s responsibility and serve to condemn him: they “kill”.
The term “Jew” (or Judah) means “praise” (cf. Genesis 29:35). Being a Jew or a Christian outwardly does not merit God’s recognition. People could be impressed by the external merits of Jewry. But it is “the honour … from God” or “the praise of God” (John 5:44; 12:43) that counts. In Philippians 3 Paul lists all the human privileges that he gave up for Christ. After that he adds what, two thousand years later, is still a fitting motto for Christians:
“Forgetting those things which are behind and reaching forward to those things which are ahead, I press forward toward the goal for the prize of the upward call of God in Christ Jesus” (vv. 13.14).