I asked: Messenger of Allah! what is party spirit? He replied: That you should help your people in wrongdoing. (Using translation from Abū Dāʾūd 5119)
أَنَّهَا سَمِعَتْ أَبَاهَا يَقُولُ قُلْتُ يَا رَسُولَ اللهِ مَا الْعَصَبِيَّةُ؟ قَالَ «أَنْ تُعِينَ قَوْمَكَ عَلَى الظُّلْمِ»