Romans 3

v1-8: Though the Jews did not have the monopoly on salvation, they did have privileges which the Gentiles did not.  They had the means of salvation, a clearer path to salvation, because to them "were committed the oracles of God... the Scriptures of the Old Testament... and those  types, promises, and prophecies that relate to Christ and the Gospel."

v9-18: The whole human race, both Jews and Gentiles, is under the guilt of sin "by which we bound to eternal ruin and condemnation," and under the power of sin which displays itself in "an inherent failure in everything good" and "an inherent bias toward everything that is evil."

v19-31: Corrupt humans could never gain acceptance with God by any works of their own.  We are all sinners by nature and by practice and failed in what is the aim of humanity, which is to glorify God. "We can never be justified and saved by the law that we have broken."  Nothing that we can do will atone for our former guilt.  Justification is only by faith in Christ's righteousness - the righteousness of God - "a righteousness that he has ordained, provided, and accepts," and which He gives to us.