Blaming God

Whenever the judgement of God is affirmed there will always be the reaction by some that God is not fair or trustworthy.
Paul knows that in ironing out the differences between Jew and Gentile and leaving them all under sin he must counter the accusation that his gospel dumps the Jews in favour of the Gentiles - exposing his gospel to the accusation that it portrays a God who has left His own covenant people out in the cold.
Where is the justice in that?
Furthermore if human evil shows how good and righteous God is, what right does He have to condemn?
Surely such a gospel encourages sin in order to enhance God’s glory.
Let’s discover how Paul responds to such questions in a way which shows that God remains faithful and blameless in spite of our doubts to the contrary.