Whenever we do something wrong, then, from now on we will not blame anything except the opinion on which it’s based; and we will try to root out wron… - Epictetus

[I]f you gape after externals, you must of necessity ramble up and down in obedience to the will of your master. And who is the master? He who has the power over the things which you seek to gain or try to avoid.

[A] man ought to be prepared in a manner for this also, to be able to be sufficient for himself and to be his own companion. [...] [S]o ought we also to be able to talk with ourselves, not to feel the want of others also, not to be unprovided with the means of passing our time; to observe the divine administration and the relation of ourselves to everything else; to consider how we formerly were affected toward things that happen and how at present; what are still the things which give us pain; how these also can be cured and how removed; if any things require improvement, to improve them according to reason.

When then any man assents to that which is false, be assured that he did not intend to assent to it as false, for every soul is unwillingly deprived of the truth, as Plato says; but the falsity seemed to him to be true.