The French philosopher Pierre-Hyacinthe Azaïs (1766-1845) formalized the statement that good and evil fortune are exactly balanced in that they produce for each person an equivalent result. Richard Arnold Epstein
Now, king of the Lacedæmonians, take care when we come out that no one sees us weeping or doing anything unworthy of Sparta. This lies in our own power; but good or evil fortune befalls us according to the will of Heaven. Plutarch
Behold a worthy sight, to which the God, turning his attention to his own work, may direct his gaze. Behold an equal thing, worthy of a God, a brave man matched in conflict with evil fortune. Seneca