As the Roman Empire became Christianized, church leaders were assigned increasing civic responsibilities. By Augustine's time, Roman law empowered a city's Christian bishop to impose a settlement, by arbitration, on consenting parties….

Augustine's reputation for fairness brought many litigants—pagans, heretics, and Christians. On occasion he would skip all his meals in order to settle the cases before him that day.

Some situations pitted the principles of justice and mercy against each other. In 408 at Calama, where Augustine's friend Possidius was bishop, local pagans staged two riots. They raided the deacon's lodging, killed a monk in the street, and went looking for Possidius, who heard from his hiding place, "Where's the bishop? If we don't get him, we'll have wasted our time!"

Peace officers did nothing to stop the violence and looting. But when the rebels came to their senses, they realized how serious their acts were. So when Augustine came to Calama a bit later to visit Possidius, a group approached him, begging him to intercede for them.

Nectarius, a respectable pagan in the group, wrote to Augustine urging him to use his influence so that extreme penalties (torture and execution) could be avoided. Nectarius admitted that the rioters should be punished, but it is not for a bishop, he argued, to seek anything but the welfare of individuals and to obtain pardon from omnipotent God for the offenses of others.

Augustine replied that, while he had no desire to see anyone tortured or executed, he did wish to see justice served. Also, as similar acts of terrorism (perpetrated by both pagans and heretics) were on the rise throughout the empire, he hoped the Calama case would serve as an example to other would-be rioters.

After eight months of inaction, the government imposed heavy penalties on the pagans, though not the death penalty.

Nectarius again appealed to Augustine, asking for a general pardon because "as the Stoics were in the habit of saying, all sins were equally great," and no one deserved special censure. This Augustine would not endorse, and he removed himself from the matter.