Direct quotation
Against Julian 3.18.35
“And how will God judge the world? For if God’s truth has abounded through my lie to his glory, why am I still judged as a sinner?” (Romans 3:6–7)
By these words the apostle shows that God would have lost the authority to judge if he had not kept within proper bounds in commanding.
The apostle said this to restrain those who maintained that the sins of mortals increase God’s praise, and that he therefore commanded impossible things in order to provide himself with an occasion for mercy. This judgment of the apostle shows that human beings are rightly judged because they failed to do what was possible. They would be judged unjustly if they had failed to do things they were commanded to do but could not do.