New testament circumcision of heart
In the New Testament, the concept of circumcision of the heart is a metaphorical expression that refers to the spiritual transformation that occurs when a person turns to God through faith in Jesus Christ. This idea is rooted in the Old Testament, where circumcision was a physical sign of the covenant between God and his people, Israel.
In the New Testament, the apostle Paul writes extensively about the concept of circumcision of the heart. In his letter to the Romans, Paul argues that the true circumcision is not a physical act, but rather a spiritual one (Romans 2:25-29). He writes:
"Circumcision is nothing and uncircumcision is nothing. What counts is the new creation. And all who will live godly in Christ Jesus will suffer persecution. As for you, you were separated from Christ, you who were called to be a saint in association with those who in former times put confidence in the flesh. You did not run with others who were running for the same goal. Instead, you ran lawlessly. All of them are Israelites, and they all have Moses' covenant. They are the fathers and from them is the human race. But it is not as though the word of God had failed. For not all those who are descended from Israel are Israel. Nor are all Abraham's children his descendants. But 'It is through Isaac that descendants will be reckoned.' That is, it is not the children by physical descent who are Abraham's children, but 'through the promise' they are counted as Abraham's children. For this is what the promise said: 'At the appointed time, I will return, and Sarah will have a son.' And not only that, but also when Rebecca had conceived children by one man, our forefather Isaac, though they were not yet born and had not done anything good or bad—in order that God's purpose in election might stand: not by works but by him who calls—she was told, 'The older will serve the younger.' Just as it is written: 'Jacob I loved, but Esau I hated.'"
(Paul is quoting Genesis 21:12 and Malachi 1:2-3)
Paul is saying that physical circumcision is not the point, but rather the spiritual transformation that occurs when a person turns to God through faith in Jesus Christ. This spiritual circumcision is what truly matters, and it is what sets apart those who are truly God's people from those who are not.
In his letter to the Galatians, Paul writes:
"You foolish Galatians! Who has bewitched you? Before your very eyes Jesus Christ was clearly portrayed as crucified. I would like to learn just one thing from you: Did you receive the Spirit by the works of the law, or by believing what you heard? Are you so foolish? After beginning by the Spirit, are you now finishing by the flesh? How foolish! You began with the Spirit, ended by the flesh. Did you experience so many things in the presence of the Christ without benefiting by them? If indeed it was because of the flesh, then that which benefits you was destroyed. Give yourselves to God. Or do you boast about something? What do you have that you did not receive? And if you did receive it, why do you boast as though you did not?"
(Galatians 3:1-5)
Paul is saying that the true circumcision is not a physical act, but rather a spiritual one that occurs when a person turns to God through faith in Jesus Christ. He is warning the Galatians against trying to earn their salvation through good works or the law, and instead encouraging them to trust in God's grace and mercy.
In summary, the concept of circumcision of the heart in the New Testament refers to the spiritual transformation that occurs when a person turns to God through faith in Jesus Christ. It is a metaphorical expression that emphasizes the importance of spiritual renewal and transformation over physical rituals or practices.