One enemy can do more hurt ...

One enemy can do more hurt than ten friends can do good.
One enemy can do more hurt than ten friends can do good.

Quotes from the same author

Discovery consists of seeing what everybody has seen and thinking what nobody else has thought.
Men are happy to be laughed at for their humor, but not for their folly.
The two maxims of any great man at court are, always to keep his countenance, and never to keep his word.
Men of great parts are often unfortunate in the management of public business, because they are apt to go out of the common road by the quickness of their imagination.
Men who possess all the advantages of life are in a state where there are many accidents to disorder and discompose, but few to please them.