The Book on Government (Kitab Al-Imara)
Muslim :: Book 20 : Hadith 4561
It has been narrated on the authority of Ibn 'Abdullah al-Bajali that the Messenger of Allah (may peace be upon him) said: One who is killed under the banner of a man who is blind (to his just cause), who raises the slogan of family or supports his own tribe, dies the death of one belonging to the days of Jahiliyya.