Central to that reality of unity is faith. Faith is more than just assenting to propositions about the nature of reality. Faith is more than believing what you are told to believe. Faith is accepting God’s reality. Faith is attempting to live in that reality of a Kingdom come, where Jesus was raised from the dead and made us right with God.
Paul tells the people of Rome (and us) that we are like the great patriarch Abraham. Abraham was made righteous because of his faith, not because he was circumcised or because he was a good person (go read Genesis 12 and following and you’ll see what mean). For Paul, and for us, this is wonderful news. Essentially it means that it doesn’t matter who you are. If you have faith, but are a Goth from the north, you are saved. If you have faith, but are a slave in a senator’s house, you are saved. If you are a Jew from Alexandria and have faith, you are saved because of that faith.
Paul wants us to know that God is not limiting his blessing anymore. We, the Gentiles, the forgotten, the broken, are now part of God’s story. Because of Jesus we have the joy that David spoke about 3000 years ago:
Oh, what joy for those whose disobedience is forgiven, whose sins are put out of sight.
Yes, what joy for those whose record the LORD has cleared of sin.