Deuteronomy 30:6 [Moses told Israel]
6And 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.
Jeremiah 31:31–34
31 “Behold, the days are coming, declares the Lord, when I will make a new covenant with the house of Israel and the house of Judah, 32 not like the covenant that I made with their fathers on the day when I took them by the hand to bring them out of the land of Egypt, my covenant that they broke, though I was their husband, declares the Lord. 33 For this is the covenant that I will make with the house of Israel after those days, declares the Lord: I will put my law within them, and I will write it on their hearts. And I will be their God, and they shall be my people. 34 And no longer shall each one teach his neighbor and each his brother, saying, ‘Know the Lord,’ for they shall all know me, from the least of them to the greatest, declares the Lord. For I will forgive their iniquity, and I will remember their sin no more.”
Ezekiel 36:24–27
24 I will take you from the nations and gather you from all the countries and bring you into your own land. 25 I will sprinkle clean water on you, and you shall be clean from all your uncleannesses, and from all your idols I will cleanse you. 26 And I will give you a new heart, and a new spirit I will put within you. And I will remove the heart of stone from your flesh and give you a heart of flesh. 27 And I will put my [Holy] Spirit within you, and cause you to walk in my statutes and be careful to obey my rules.
Romans 2:28–29
28 For no one is a Jew who is merely one outwardly, nor is circumcision outward and physical. 29 But a Jew is one inwardly, and circumcision is a matter of the heart, by the Spirit, not by the letter. And I will remove the heart of stone from your flesh and give you a heart of flesh. 27 And I will put my [Holy] Spirit within you, and cause you to walk in my statutes and be careful to obey my rules.
I find it remarkable that Paul takes Moses’ brief phrase in Deuteronomy—“circumcise your heart”—and builds an entire theology of true covenant identity from it. Out of 580,000 words in the OT, Paul seizes this three-word command to show that a true Jew is not one outwardly, but one whose heart has been transformed by God (Rom. 2:28–29). God has circumcised the heart of a true Israelite.
To “circumcise” means to cut away. Spiritually, this is the work of the Holy Spirit: He figuratively cuts out the heart of stone, gives a heart of flesh, and writes God’s law on it. With this circumcised heart, a person believes the promises of the gospel (Rom. 10:9–10), loves God, and learns to love others. In short, the new heart produces both faith and obedience.
Jeremiah 31:34 confirms this: “They shall all know me.” The “all” refers to everyone whose heart Yahweh has circumcised. Jesus echoes the same truth in John 3, where He tells Nicodemus that he needs to be born again to see and enter the Kingdom of God. Then Jesus made it clear that this birth from above is the work of the Holy Spirit. In the same way that the circumcision of the heart is not a physical circumcision, the second birth is not a physical birth. In both, the Spirit of Yahweh brings salvation to those who believe.
Paul ties all this together in Titus 3:5: God saved us not by our works of righteousness but by the washing of regeneration and renewal of the Holy Spirit. Paul pulls together OT and New Covenant language to teach us that circumcision of the heart, new birth, cleansing, and renewal are different images pointing to the same reality: the Spirit’s work of regeneration under the New Covenant. This is the work of the Triune God, for as Jonah reminds us, “Salvation belongs to the LORD” (Jonah 2:9).
