What does Romans 4 teach about faith and righteousness?

Romans 4 articulates the core principle that righteousness before God is credited through faith rather than human works. The chapter recounts the life of Abraham, demonstrating that he was justified by his faith in God's promise before the law was given. His belief that God would fulfill His covenant made him righteous in God's sight. This shows that all believers, Jew and Gentile, are justified in the same manner—through faith alone. This reinforces the Reformed understanding of salvation, revealing that human efforts cannot contribute to righteousness, and emphasizing that it is Christ's righteousness, received by faith, that justifies sinners.