The Golden Sayings of Epictetus by Epictitus Part 2 Page 10

things free and all your own, you do not use them! you do not perceive what it is you have received nor whence it comes, but sit moaning and groaning; some of you blind to the Giver, making no acknowledgment to your Benefactor; others basely giving themselves to complaints and accusations against God.

Yet what faculties and powers you possess for attaining courage and greatness of heart, I can easily show you; what you have for upbraiding and accusation, it is for you to show me!