A friend is a person with whom I may be sincere. Before him, I may think aloud.
Ralph Waldo Emerson (1803-1882) 

A friend is one who knows us, but loves us anyway.
Fr. Jerome Cummings 

A real friend is one who walks in when the rest of the world walks out.
Walter Winchell 

A true friend is one who overlooks your failures and tolerates your successes.
Doug Larson 

A true friend is someone who is there for you when they would rather be someplace else.
Len Wein 

A woman may very well form a friendship with a man, but for this to endure, it must be assisted by a little physical antipathy.
Friedrich Nietzsche (1844-1900) 

Advice from your friends in like the weather, some of it is good, some of it is bad.
Anonymous 

Am I not destroying my enemies when I make friends of them?
Abraham Lincoln (1809-1865) 

Books, like friends, should be few and well chosen.
Samuel Paterson 

Friends may come and go, but enemies accumulate.
Thomas Jones