Or do you think lightly of the riches of His kindness and tolerance and patience, not knowing that the kindness of God leads you to repentance? Romans 2:4
True belief that lives by faith repents.
To repent is to change one’s mind and as a result, change one’s course. God, who is rich in kindness, tolerance, and patience, gave us the gospel so that we could be saved by belief in this good news (Rom. 1:16), but that belief must be coupled with repentence, otherwise we would be taking advantage of God’s kindness.
According to Romans chapter 2, the person who repents changes their course by persevering in doing good. They don’t just tell people to follow after good, they live it themselves. They practice what they preach. They’re not hypocrites. Their aim is to honor God with their actions, not dishonor Him.
The driving force behind all of this is the change of heart that true belief produces. The Jews thought they could continue to obey unrighteousness and their circumcision would justify them, but Paul is very clear that following the letter of the law is not what would justify them. What they really needed was a circumcision of the heart by the Spirit. That kind of heart would be seeking for eternal life, thus would change course by hearing the truth and obeying it. That repentant heart would not get praise from men, but from God.
But he is a Jew who is one inwardly; and circumcision is that which is of the heart, by the Spirit, not by the letter; and his praise is not from men, but from God. Romans 2:29