Epictetus, Golden Sayings 20

Seeing this then, and noting well the faculties that you have, you should say—"Send now, O God, any trial that You will! I have the means and powers given me by You to acquit myself with honor through whatever comes to pass!"

No, but there you sit, trembling for fear that certain things should come to pass, and moaning and groaning and lamenting over what does come to pass. And then you upbraid the Gods. Such meanness of spirit can have but one result—impiety.
 
Yet God has not only given us these faculties by means of which we may bear everything that comes to pass ,without being crushed or depressed by them. But like a good King and Father, He has given us this without limit or hindrance, placed wholly at our own disposition, without reserving to Himself any power of impediment or restraint.

Though possessing all these things free and as all you own, you do not use them! You do not perceive what it is you have received, nor from where 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 the upbraiding and accusation, it is for you to show me!