Sahih Bukhari Volume 008, Book 073, Hadith Number 061.

Narated By Masruq : We were sitting with 'Abdullah bin 'Amr who was narrating to us (Hadith): He said, "Allah's Apostle was neither a Fahish nor a Mutafahhish, and he used to say, 'The best among you are the best in character (having good manners).'"