It was narrated that Abu Jabirah bin Dahhak said: (Allah's saying) "Nor insult one another by nicknames." was revealed concerning us, the Ansar. When the Prophet(saw) came to us, a man among us would have two or three names, and the Prophet(saw) might call him by one of those names, only to be told: "0 Messenger of Allah, he does not like that name." Then: "Nor insult one another by nicknames." was revealed." (Sahih)