There is one word which may serve as a rule of practice for all one's life -reciprocity.
The Man who says he can, and the man who says he can not.. Are both correct
If a man keeps cherishing his old knowledge so as continually to be acquiring new, he may be a teacher of others.
All people are the same; only their habits differ.
Looking at small advantages prevents great affairs from being accomplished.
A man of wisdom delights in water.