The Sun visits cesspools without being defiled.

No man is hurt but by himself.

To arrive at perfection, a man should have very sincere friends or inveterate enemies; because he would be made sensible of his good or ill conduct, either by the censures of the one or the admonitions of the other.

Antisthenes used to say that envious people were devoured by their own disposition, just as iron is by rust. Envy of others comes from comparing what they have with what the envious person has, rather than the envious person realising they have more than what they could have and certainly more than some others and being grateful. It is really just an inability to get a correct perspective on their lives.

If your cloak was a gift, I appreciate it; if it was a loan, I'm not through with it yet.

When I look upon seamen, men of science and philosophers, man is the wisest of all beings; when I look upon priests and prophets nothing is as contemptible as man.

Democritus says, "But we know nothing really; for truth lies deep down".