Justification by faith alone means we cannot boast. It means both Jews and Gentiles are justified the same way.

The Means of Obtaining the Righteousness of God - Romans 3:24-26

How God Justifies Sinners

You can believe in the goodness of humanity for all you want, but the evidence of depravity is all around us.

Objections to Condemnation: Romans 3:5-8

Paul is most likely addressing a common question arising from the Jews in his frequent teachings in the synagogue.