The healthy eye ought to see all visible things and not to say, I wish for green things; for this is the condition of a diseased eye.

Be satisfied with your business, and learn to love what you were bred to.

We are born for cooperation

Always follow these two rules: first, act only on what your reasoning mind proposes for the good of humanity, and second, change your opinion if someone shows you it's wrong. This change of mind must proceed only from the conviction that it's both correct and for the common good, but not because it will give you pleasure and make you popular.

Things that have a common quality ever quickly seek their kind.

But if anything in thy own dispositiongives thee pain, who hinders thee from correcting thy opinion? And even if thou art pained because thou art not doing some particular thing which seems to thee to be right, why dost thou not rather act than complain?- But some insuperable obstacle is in the way?- Do not be grieved then, for the cause of its not being done depends not on thee.- But it is not worth while to live if this cannot be done.- Take thy departure then from life contentedly, just as he dies who is in full activity, and well pleased too with the things which are obstacles.

A noble man compares and estimates himself by an idea which is higher than himself; and a mean man, by one lower than himself. The one produces aspiration; the other ambition, which is the way in which a vulgar man aspires.