Letters 66.13

What? Do you not think that the virtue of him who bravely storms the enemy’s stronghold is equal to that of him who endures a siege with the utmost patience? Great is Scipio when he invests Numantia, and constrains and compels the hands of an enemy, whom he could not conquer, to resort to their own destruction. Great also are the souls of the defenders—men who know that, as long as the path to death lies open, the blockade is not complete, men who breathe their last in the arms of liberty. In like manner, the other virtues are also equal as compared with one another: tranquillity, simplicity, generosity, constancy, equanimity, endurance. For underlying them all is a single virtue—that which renders the soul straight and unswerving.

Seneca, Letters to Lucilius 66.13, translated by Richard Mott Gummere