On the one hand it is true that God’s nature and truth must be revealed even through evil so that he may be glorified (Romans 3:7): But if through my lie God’s truth abounds to his glory, why am I still being condemned as a sinner?
Israel’s history proves God to be right; his somber words in Deuteronomy 32:1–52 are trustworthy. But then the question arises that if even evil serves to vindicate God, why then is it still judged? Why then the judgment over David and Paul himself? The apostle plainly asks: Why am I still being condemned as a sinner?
Is it not enough that God can be glorified in the world (since Israel’s sinfulness vindicates him with regard to his expectations of this people)? Can it not simply be left at that so that no further legal action is taken against Israel? The answer was already implied in Romans 3:4: God’s faithfulness demands that the judgments he has proclaimed be executed without showing any favouritism. God is being blasphemed among the people of Israel through their lies and sins (Romans 2:24) and because of this he can only be glorified through his judgments executed firstly over the Jew and then also over the Greek. After all, if God were to simply drop the case against the people of Israel, how would there then ever be a (redeeming and vindicating) judgment over the ungodly world (Romans 3:6b)?
Paul therefore in Romans 3:8 strongly rejects the insinuation that he or any of the other apostles might be suggesting that sinning can be done in order to effectuate something good. [S]ome people slanderously charge us with saying [this, but] their condemnation is just.
The slander referred to here probably comes from Paul’s own kinsmen. They based their argument on the distorted idea that, in their ministry to the Gentiles (specifically by not demanding that they be circumcised), Paul and others actually emboldened sinners (see Acts 21:21, Acts 21:28)—as if Paul intended to eliminate God’s righteous judgment. The apostle counters this accusation by noting that those who spread such slander will certainly mark that there is a judgment.1
7 But if through my lie God’s truth abounds to his glory, why am I still being condemned as a sinner?