The Book of Romans is a four-part explanation of the Gospel message written by Paul to the Church in Rome. Since Adam, humans chose to live sinful and selfish lives. The people of Israel tried to obey God and follow the Law, but they didn't succeed. Only faith in Jesus' death and resurrection can justify humanity and fulfill God's promise to create a covenant relationship with His people, the descendants of Abraham.
Through Jesus, God creates a new covenant family that includes Jews and gentiles who are unified as they love and forgive each other. Even though people continue to reject Jesus, God uses their rejection to expand His family and grow the Church.