In this text, Paul follows on from the idea that mankind - Jew or Gentile - is justified by faith alone.
Righteousness, Salvation, and Faith are through Christ alone.
Is Salvation too free? Paul answers objections to the forgiveness of sins in Christ.
Is God's wrath and judgement justified?
Rejecting God leads to sin, which leads to death. There are consequences for sin both now and in the future.
God has made himself known in creation, and while we devise many ways to disbelieve, we are without excuse.