He who is not angry when there is just cause for anger is immoral. Why? Because anger looks to the good of justice. And if you can live amid injustice without anger, you are immoral as well as unjust.
St. Thomas Aquinas (c. 1225-1274), Italian Catholic priest and Dominican, theologian and philosopher.
And a comment from me: The challenge, of course, is to be moral in our anger. This is why I am so thankful for the teachings of Ghandi and Martin Luther King, Jr. on nonviolence. Paige Schilt recently wrote a wonderful essay on living out those teachings as a participant in Soulforce‘s American Family Outing at the Bilerico Project.
And an aside: This quote is widely attributed to St. Thomas, but after scouring the sections from Summa Theologica where one might expect to find it, I came up empty handed. Perhaps it’s from Contra Gentiles? If anyone can help me attribute this one, I’d be grateful.