I asked, "Messenger of Allah, what is tribal partisanship?"He replied, "That you support your people in wrongdoing."
حدثنا محمود بن خالد الدمشقي حدثنا الفريابي حدثنا سلمة بن بشر الدمشقي
قلت يا رسول الله ما العصبية قال أن تعين قومك على الظلم
[Its chain of transmission is daif] Bayhaqi narrated it, 10/234, from the hadith of Abu Dawud with the same wording, and it contains a serious defect between Salama bin Bishr (of unknown status) and the daughter of Wathila. Abbad bin Kathir is extremely daif, and through his route Ibn Majah narrated it, hadith no. 3949.