The book of Romans is so masterfully written by the apostle Paul. He addresses every objection and concern that would be raise with someone hearing the true gospel. In the previous verses, Paul explained that even though the Jews were not faithful to God, God was still faithful the them.
When we look at how unfaithful we are, it magnifies the mercy of God in an exponential way. So the natural question arises...'if our unrighteousness brings out God's righteousness more clearly, what shall we say? That God is unjust in bringing his wrath on us?" Or in other words, if our sin promotes and amplifies God's holiness and grace, why am I being judged?
Although Paul is addressing this argument, he clearly defines it as a human argument. The very thought that our sin could benefit God and help to promote His character is a very carnal and self-seeking. Paul wants to make that point understood from the beginning. Therefore he gives a disclaimer, that it in no way was this wisdom of God, this logic was clearly man made.
Paul's answer to this question is a strong, God forbid! The implications that God would be unjust or unfair to judge the world is utterly ridiculous. Our sin does bring out His mercy more clearly, however God can judge the world because He alone is righteous, holy and sinless. It is an established fact that He will come back the second time to judge, so the argument that God is unfair by judging the world has to be thrown out on that basis.
Apparently, Paul preached the message of grace so strongly that when people heard it, questions arose and truth had to be explained. God's message of grace is so great that it is natural to ask these types of questions. If you don't, then you probably haven't heard the full gospel as Paul preached it. Today, thank the Lord for His abundance of mercy and grace pour out upon you.