Is anything added to believing in Christ in order to receive God's righteousness?
No. God's righteousness is received through faith in Jesus Christ, with nothing added. Scripture states it is "by faith of Jesus Christ unto all and upon all them that believe, plus nothing." The law and its deeds are excluded; there is no difference between Jew and Gentile.
Les explains from Romans 3:21 that the righteousness of God is now manifested without the law, though it was witnessed by the law and the prophets. He stresses that this righteousness is by faith of Jesus Christ unto all and upon all them that believe—“plus nothing,” with anything else added. Les notes that we always have to know what we believe, but Paul’s point is that there is no difference, specifically no difference between Jew and Gentile. This is what got Paul in trouble with his Jewish people, because God had earlier set Israel apart from Egypt and told them to be different and separate from the pagans. Even so, Paul maintains there is no difference, for all have sinned and come short.
Even the righteousness of God which is by faith of Jesus Christ unto all and upon all them that believe: for there is no difference:
More Questions
What does Romans 3:22 say is required to receive the righteousness of God?
The righteousness of God comes through faith of Jesus Christ to everyone who believes, and nothing else is added to that faith.