There had been a riot in the Greek city of Thessalonica and one of Theodosius' officials had been murdered. In response, Theodosius had done what emperors always do. He sent in the army to teach the people of Thessalonica, and by extension the rest of the empire, a lesson. Some 7,000 people – men, women, and children – were killed, the vast majority of whom had had nothing to do with the death of the official.
Ambrose knew that the emperor's actions needed to be condemned even if it meant the very real possibility of his being sent to prison or killed. Emperors don't usually like to be challenged. In addition, Ambrose had reason to be favorably inclined to Theodosius as a political ally since he had made Christianity the official faith of the Empire. It was not only dangerous, but also politically inexpedient for Ambrose to confront Theodosius. He did it anyway. Against all odds, Emperor Theodosius repented and publicly sought absolution from his bishop.
I thank God for Ambrose's example of courage and integrity.
After all, he was the Emperor who had made Christianity the official faith of the Empire. Were there theologians or evangelists around to reassure him that his use of force was necessary and justified for the law and order of the Empire? Were there defenders of the Emperor who argued that “sometimes you put your Christian values on pause to get the work done”? After all, you don’t want “a Sunday School teacher or pastor” running the empire. You shouldn't "look to the teachings of Jesus for what my political beliefs should be.” You don’t “want some meek and mild leader or somebody who's going to turn the other cheek.” You want “the meanest, toughest SOB you can find to protect the nation.”
That was not Ambrose's take. I am thankful that Ambrose was not willing to compromise his integrity as a follower of Jesus. I am grateful that he was no political lackey or sycophant. I am glad he was willing to stand for the Gospel and call the most powerful and dangerous member of his congregation to account for failing to lead and serve in a Christlike manner. And I am grateful that, as a Christian, Theodosius knew what it meant to ask for God's forgiveness and repented.
See also: Jerome the Ciceronian