Meditations, Book 8, Section 45

Marcus Aurelius — The Emperor

If something outside you causes grief, know that it's not the thing itself that hurts you. It's your judgment about it. You can change that judgment whenever you want.

If something wrong in your own character causes grief, can't you fix your beliefs and opinions? If you're upset that you're not doing what seems right and just, why not just do it instead of being upset?

But maybe something stronger than you gets in the way. Then don't feel bad if it's not your fault the thing doesn't get done. 'But this thing is so important that life isn't worth living unless I do it.' If that's true, then as long as you stay kind and loving toward everyone, you can leave this life. Even then — especially then — you're doing well when you die with goodwill toward those who stood in your way.

Marcus Aurelius — The Emperor Original

If therefore it be a thing external that causes thy grief, know, that it is not that properly that doth cause it, but thine own conceit and opinion concerning the thing: which thou mayest rid thyself of, when thou wilt. But if it be somewhat that is amiss in thine own disposition, that doth grieve thee, mayest thou not rectify thy moral tenets and opinions. But if it grieve thee, that thou doest not perform that which seemeth unto thee right and just, why doest not thou choose rather to perform it than to grieve? But somewhat that is stronger than thyself doth hinder thee. Let it not grieve thee then, if it be not thy fault that the thing is not performed. 'Yea but it is a thing of that nature, as that thy life is not worth the while, except it may be performed.' If it be so, upon condition that thou be kindly and lovingly disposed towards all men, thou mayest be gone. For even then, as much as at any time, art thou in a very good estate of performance, when thou doest die in charity with those, that are an obstacle unto thy performance.