Romans 2:25-27

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 [or even though you who, by means of a] written code and circumcision, are a lawbreaker.

This is the last hypothetical attempt by the Jews to counter Paul’s insistence that they need the gospel. And this one was Paul’s favorite to refute! Paul moves from a discussion of the value of the moral law to a discussion of the value of the ceremonial law. Circumcision was a sign of the covenant that God made with Abraham. And the Jews final effort to deny their need for Paul’s gospel was to run to this sign of the covenant. This was their proof that they were special to God. And Paul ripped their hopes to shreds when he made it clear that covenant signs (circumcision of the flesh) mean nothing apart from covenant realities (circumcision of the heart).

Paul is addressing unbelieving Jews who have assurance of their salvation. There are believers who have assurance, believers who lack assurance, unbelievers who lack assurance, and unbelievers who have a false assurance. Paul loves to preach to unbelievers without assurance. They are one step from the kingdom. They are not saved, and they know it. They are ripe to hear the gospel. Paul loves to preach the gospel to believers who lack assurance because he can assure them and the promises of God made to them, that they have not fully realized yet, and moved them into spiritual maturity where they can be secure in their faith. He loves to preach the gospel to believers who have assurance because they grow in their obedience of faith and sanctification. But those unbelievers who have assurance, they are a hard nut to crack. So Paul is throwing out every argument to undercut their false assurance, not because he hates the Jewish people, not because he doesn’t care about them, but precisely because he loves them. He does not want them to be spiritually deluded. He does not want them to be secure when they should not be. And so he’s cutting down every place they run to encourage them to run to Jesus Christ for assurance. The law will condemn. Their understanding of election is faulty. Their Jewish heritage was bankrupt. And now circumcision, it is empty. In Christ alone is salvation.