One of the main problems the Jews had in Paul’s time was that they forgot that God wasn’t so interested in outward appearances as he was in their hearts.
In particular, they thought it was circumcision that made them right before God, all the while ignoring the sin that was in their hearts.
God had made that problem clear through the Old Testament prophets. In Jeremiah, he said,
The days are coming…when I will punish all who are circumcised only in the flesh — Egypt, Judah, Edom, Ammon, Moab and all who live in the desert in distant places.
For all these nations are really uncircumcised, and even the whole house of Israel is uncircumcised in heart. (Jeremiah 9:25-26)
In other words, God wasn’t so interested in people cutting off parts of their body. He was interested in having their hearts. And if he didn’t have their hearts, circumcision meant nothing to him.
And so Paul said,
Circumcision has value if you observe the law, but if you break the law, you have become as though you had not been circumcised.
If those who are not circumcised keep the law’s requirements, will they not be regarded as though they were circumcised?
The one who is not circumcised physically and yet obeys the law will condemn you who, even though you have the written code and circumcision, are a lawbreaker.
A man is not a Jew if he is only one outwardly, nor is circumcision merely outward and physical.
No, a man is a Jew if he is one inwardly; and circumcision is circumcision of the heart, by the Spirit, not by the written code. Such a man’s praise is not from men, but from God. (Romans 2:25-29)
Again, Paul is speaking mostly hypothetically.
He’s saying that if someone were able to keep the law perfectly, even though he were not circumcised, God would accept them.
On the other hand, if a circumcised person doesn’t keep the law, God will condemn them as a lawbreaker. And for that matter, the law-keeping uncircumcised person could do the same.
Of course, no one, circumcised or not, has ever been able to keep the law perfectly.
So Paul tells them, “You’re not a Jew, that is, you are not truly God’s chosen people if you are simply circumcised, because circumcision isn’t merely physical. It’s a matter of the heart.
Only if your heart is circumcised by the Spirit of God are you truly accepted by God and can be called his people.”
What does it mean to have a circumcised heart? Paul tells us in Colossians 2:11.
In him you were also circumcised, in the putting off of the sinful nature, not with a circumcision done by the hands of men but with the circumcision done by Christ. (Colossians 2:11)
In other words, when we came to Christ, he cut off the chains that bound us to the sinful nature.
Prior to that, we were pulled around by that nature and acted in accordance with it. But now, that nature has been circumcised and we belong to God.
And having been set free from that sinful nature, we are free to follow after God and have been given the power to live a righteous life.
But again, that circumcision is not done by our own efforts, but by giving our hearts to Christ, by coming to him in faith, and saying, “Lord Jesus I need you. I can’t save myself. Please save me.
I’m putting my trust in you and your work for me in the cross. Now forgive my sins and make me yours.”
And when you do, that’s when you become God’s child.
That’s when you are truly right before God.
How about you? Have you given your heart to God? Is your heart circumcised before him?
Moment to Moment (Bible blog) 