At the heart of the scriptures (that’s what he means by law and prophets), is a promise. The promise is that God will be faithful to save his people from their sin. This promise runs throughout the whole of scripture and holds the whole story together. All other religions in the world are based on you making and keeping promises to the ‘gods’ in hopes of earning love and acceptance. The one true God, however, because of His great love, has promised to save us based on his faithfulness. Justification and righteousness are the results of God being faithful to what has been revealed in scripture. From the very beginning, every promise of salvation was pointing forward to Jesus. And now because He is faithful, what is required of us: is to believe!
Righteousness is not something we produce, it’s something God provides!