It has been narrated on the authority of Ibn 'Abdullah al-Bajali that the Messenger of Allah (ﷺ) 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.
حَدَّثَنَا هُرَيْمُ بْنُ عَبْدِ الأَعْلَى، حَدَّثَنَا الْمُعْتَمِرُ، قَالَ سَمِعْتُ أَبِي يُحَدِّثُ، عَنْ أَبِي، مِجْلَزٍ عَنْ جُنْدَبِ بْنِ عَبْدِ اللَّهِ الْبَجَلِيِّ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم ‏ "‏ مَنْ قُتِلَ تَحْتَ رَايَةٍ عُمِّيَّةٍ يَدْعُو عَصَبِيَّةً أَوْ يَنْصُرُ عَصَبِيَّةً فَقِتْلَةٌ جَاهِلِيَّةٌ ‏"‏ ‏.‏
Reference : Sahih Muslim 1850
In-book reference : Book 33, Hadith 89
USC-MSA web (English) reference : Book 20, Hadith 4561
  (deprecated numbering scheme)