Romans 3:5-6: But If Our Unrighteousness Serves To Show The Righteousness of God, What Shall We Say?
 But if our unrighteousness serves to show the righteousness of God, what shall we say? That God is unrighteous to inflict wrath on us? (I speak in a human way.)  By no means! For then how could God judge the world? (ESV)
The Apostle Paul had his critics. This should come as no surprise. Paul is challenging Jews and Gentiles alike. He is telling the Jews to abandon the Jewish Law. He is telling the Gentiles to abandon their idolatry. Together, all of them are invited to place their faith in Jesus Christ, who died for the sins of all; Jews and Gentiles.
One of the criticisms of Paul's teaching is that he was condoning sin. For the Jews they see Paul as not holding them to the strict following of the Old Testament Law. For the Gentiles he tells them they can be completely forgiven of their grievous sins that were against God, even though they did not have the Law that the Jews had.
Paul poses an argument to his critics. He is basically saying, "If all our sin shows how much more glorious God's holiness is, what's wrong with our sin? We are making God look good!" He rejects that argument completely saying, "By no means!" The argument that Paul makes is the very argument that his critics were making.
Paul is not saying God is easy on sin. On the contrary, he is a righteous judge. He is not unrighteous to inflict wrath on mankind. So, this begs the question, "If God is a righteous judge, but forgives us of our sin, how is our judgment dealt with? Jesus Christ, God's holy son, took our judgment on his back for us at the cross. We are forgiven. He receives the payment. We call this propitiation.
God hates sin. That is why he made a way for out sin to be judged and for us to be forgiven. It is through the sacrifice of Jesus Christ on the cross. Trust him today.