Upon him whom you rightly desire to harm, against whom weapons are lawfully carried, upon him usury is legally imposed. On him whom you cannot easily conquer in war you can quickly take vengeance with the hundredth. From him exact usury whom it would not be a crime to kill. He fights without weapon who demands usury; without a sword he revenges himself upon an enemy, who is an interest collector from his foe. Therefore, where there is the right of war, there is also the right of usury. –St. Ambrose