The idea of “circumcision of the heart” is found in Romans 2:29. It refers to having a pure heart, separated unto God. Paul writes, “A Jew is one inwardly, and circumcision is a matter of the heart, by the Spirit, not by the letter.” These words conclude a sometimes confusing passage of Scripture regarding circumcision and the Christian. Verses 25-29 provide context:
“For circumcision indeed is of value if you obey the law, but if you break the law, your circumcision becomes uncircumcision. So, if a man who is uncircumcised keeps the precepts of the law, will not his uncircumcision be regarded as circumcision? Then he who is physically uncircumcised but keeps the law will condemn you who have the written code and circumcision but break the law. For no one is a Jew who is merely one outwardly, nor is circumcision outward and physical. But a Jew is one inwardly, and circumcision is a matter of the heart, by the Spirit, not by the letter. His praise is not from man but from God.”
Paul is discussing the role of the Old Testament Law as it relates to Christianity. He argues that Jewish circumcision is only an outward sign of being set apart to God. However, if the heart is sinful, then physical circumcision is of no avail. A circumcised body and a sinful heart are at odds with each other. Rather than focus on external rites, Paul focuses on the condition of the heart. Using circumcision as a metaphor, he says that only the Holy Spirit can purify a heart and set us apart to God. Ultimately, circumcision cannot make a person right with God; the Law is not enough. A person’s heart must change. Paul calls this change “circumcision of the heart.”
This concept was not original with the apostle Paul. As a Jew trained in the Law of Moses, he was certainly aware of this discussion from Deuteronomy 30. There, the Lord used the same metaphor to communicate His desire for a holy people: “And the LORD your God will circumcise your heart and the heart of your offspring, so that you will love the LORD your God with all your heart and with all your soul, that you may live” (Deuteronomy 30:6). Physical circumcision was a sign of Israel’s covenant with God; circumcision of the heart, therefore, would indicate Israel’s being set apart to love God fully, inside and out.
John the Baptist warned the Pharisees against taking pride in their physical heritage and boasting in their circumcision: “Do not think you can say to yourselves, 'We have Abraham as our father.' I tell you that out of these stones God can raise up children for Abraham” (Matthew 3:9).
True “children of Abraham” are those who follow Abraham’s example of believing God (Genesis 15:6). Physical circumcision does not make one a child of God; faith does. Believers in Jesus Christ can truly say they are children of “Father Abraham.” “If you belong to Christ, then you are Abraham’s seed, and heirs according to the promise” (Galatians 3:29).
God has always wanted more from His people than just external conformity to a set of rules. He has always wanted them to possess a heart to love, know, and follow Him. That’s why God is not concerned with a circumcision of the flesh. Even in the Old Testament, God’s priority was a spiritual circumcision of the heart: “Circumcise yourselves to the LORD, circumcise your hearts, you men of Judah and people of Jerusalem, or my wrath will break out and burn like fire because of the evil you have done” (Jeremiah 4:4).
Both Testaments focus on the need for repentance and inward change in order to be right with God. In Jesus, the Law has been fulfilled (Matthew 5:17). Through Him, a person can be made right with God and receive eternal life (John 3:16; Ephesians 2:8-9). As Paul said, true circumcision is a matter of the heart, performed by the Spirit of God.