Epictetus Quote

When therefore we are hindered, or disturbed, or grieved, let us never attribute it to others, but to ourselves; that is, to our own principles. An uninstructed person will lay the fault of his own bad condition upon others. Someone just starting instruction will lay the fault on himself. Some who is perfectly instructed will place blame neither on others nor on himself.

All the Works of Epictetus (ed. 1758)