It is one thing to live with a tyrant, another with a friend. But if a man's ears are so closed to plain speaking that he cannot bear to hear the truth from a friend, we may give him up in despair.
 Marcus Tullius Cicero, On Friendship (44 BC). copy citation

add
Author Marcus Tullius Cicero
Source On Friendship
Topic truth despair
Date 44 BC
Language English
Reference
Note Translated by E. S. Shuckburgh
Weblink http://www.gutenberg.org/files/2808/2808-h/2808-h.htm

Context

“(for I am glad to adopt Terence's word) , though there should be every courtesy, yet that base kind which assists a man in vice should be far from us, for it is unworthy of a free-born man, to say nothing of a friend. It is one thing to live with a tyrant, another with a friend. But if a man's ears are so closed to plain speaking that he cannot bear to hear the truth from a friend, we may give him up in despair. This remark of Cato's, as so many of his did, shews great acuteness: "There are people who owe more to bitter enemies than to apparently pleasant friends: the former often speak the truth, the latter never."” source