21 But now apart from the law the righteousness of God has been made known, to which the Law and the Prophets testify. 22 This righteousness is given through faith in Jesus Christ to all who believe. There is no difference between Jew and Gentile, 23 for all have sinned and fall short of the glory of God, 24 and all are justified freely by his grace through the redemption that came by Christ Jesus.
We always hear the words, "So and so is a good person." And while they may be somewhat of a good person, what does that mean?" They are better than the next person, or better than most. And what does that look like when we compare that to what Paul calls the "righteousness of God". Literally when we use this word, the original meaning is the justice of God. Or, God is always just.
Here is a good explanation of the righteousness of God,
We must then say the righteousness of God is evident in the way He consistently acts in accord with His own character. God always acts righteously; His every action is consistent with His character. God is always consistently “Godly.” God is not defined by the term “righteous,” as much as the term “righteous” is defined by God. God is not measured by the standard of righteousness; God sets the standard of righteousness. Robert Deffinbaugh
When the Jews were under the Law, God's righteousness was determined by how the Jews did, or did not, comply with God's law. When they disobeyed God's Law, they were unrighteous and deserved God's righteous judgment. It was fair. But God showed mercy to the Israelites when they cried out to him and repented of their sin. We see this process throughout the stories of the Old Testament in God's relationship with His chosen people, the Jews.
But now Paul says there is another kind of righteousness that has been given by God. It is a righteousness that can only be obtained by faith. Righteousness is given to us through a person, Jesus Christ, who is the only one who is truly righteous. Therefore, when we trust in Jesus, we are given a righteousness that is outside of us. We say we are "justified by faith", meaning we enter into a right relationship with God through trusting in the gift he has given us.
The biggest problem with the Jewish leaders was that they were "self righteous". They thought that by their good deeds and position they deserved righteousness with God. But their righteousness was like "filthy rags" in God's eyes. It did not meet God's standards because it was humanly engineered. It was not from God. That is why Paul says there is no difference between Jews and Gentiles, because they both equally need this gift of God's righteousness.
So how then do we respond the statement that someone is good person? While they may be a good person, or better than most, it still does not make them justified before God. Why? Paul says in verses 11 and 12, "There is no one who is righteous no not even one! There is no one who seeks God or understands God."
The Good News we don't have to earn God's righteousness, but it is given to us. It is the greatest gift we could ever receive, a right relationship with God. This is why we will go to heaven one day because of this right relationship. We have been justified by grace (God's gift to us) through faith (our trusting in what God has done for us). This is the classic definition of what it means to be a Christian, and the clearest definition of the Good News. Simple right? The only problem is we have to admit we are sinners and need God's grace, and then trust in what God has done for us in Jesus Christ. This goes against human nature, where we want to try to trust in our own ability to justify ourselves. Unfortunately this doesn't work because it doesn't come close to satisfying God's righteousness.