Caution: Translations of Quran and Ḥadīth may lead to possible misapplications and misinterpretations. This site is intended for students of sacred knowledge that are proficient in comprehending classical Arabic and have a strong foundation in Islamic sciences. Also note that religious injunctions rely on several aspects beyond what one may glean through reading individual aḥādīth.
Qurʾān Bukhārī Muslim Nasāʾī Abū Dāwūd Tirmidhī Ibn Mājah Mālik Aḥmad Dārimī Ḥākim Ibn Ḥibbān Ṭabarānī Nasāʾī's Kubrá Bayhaqī al-Luʾluʾ wa-al-Marjān Ibn Rajab's Fifty Riyāḍ al-Ṣāliḥīn Aḥmad's Zuhd Suyūṭī
bayhaqi:11443 – Abū ʿAlī > Abū Bakr > Abū Dāwud > ʿAlī b. al-Ḥusayn b. Ibrāhīm > ʿUmar b. Yūnus > ʿĀṣim b. Muḥammad b. Zayd al-ʿUmarī > al-Muthanná b. Yazīd > Maṭar al-Warrāq > Nāfiʿ > Ibn ʿUmar

"He who assits in a dispute unjustly deserves the anger of Allah, Most High. (Using translation from Abū Dāʾūd 3598)   

البيهقي:١١٤٤٣ – وَأَخْبَرَنَا أَبُو عَلِيٍّ أنبأ أَبُو بَكْرٍ ثنا أَبُو دَاوُدَ ثنا عَلِيُّ بْنُ الْحُسَيْنِ بْنِ إِبْرَاهِيمَ ثنا عُمَرُ بْنُ يُونُسَ ثنا عَاصِمُ بْنُ مُحَمَّدِ بْنِ زَيْدٍ الْعُمَرِيُّ حَدَّثَنِي الْمُثَنَّى بْنُ يَزِيدَ عَنْ مَطَرٍ الْوَرَّاقِ عَنْ نَافِعٍ عَنِ ابْنِ عُمَرَ

عَنِ النَّبِيِّ ﷺ بِمَعْنَاهُ قَالَ وَمَنْ أَعَانَ عَلَى خُصُومَةٍ بِظُلْمٍ فَقَدْ بَاءَ بِغَضَبٍ مِنَ اللهِ  

See similar narrations below:

Collected by Abū Dāwūd
abudawud:3598 – ʿAlī b. al-Ḥusayn b. Ibrāhīm > ʿUmar b. Yūnus > ʿĀṣim b. Muḥammad b. Zayd al-ʿUmarī > al-Muthanná b. Yazīd > Maṭar al-Warrāq > Nāfiʿ > Ibn ʿUmar

"He who assits in a dispute unjustly deserves the anger of Allah, Most High.  

أبو داود:٣٥٩٨ – حَدَّثَنَا عَلِيُّ بْنُ الْحُسَيْنِ بْنِ إِبْرَاهِيمَ حَدَّثَنَا عُمَرُ بْنُ يُونُسَ حَدَّثَنَا عَاصِمُ بْنُ مُحَمَّدِ بْنِ زَيْدٍ الْعُمَرِيُّ حَدَّثَنِي الْمُثَنَّى بْنُ يَزِيدَ عَنْ مَطَرٍ الْوَرَّاقِ عَنْ نَافِعٍ عَنِ ابْنِ عُمَرَ

عَنِ النَّبِيِّ ﷺ بِمَعْنَاهُ قَالَ وَمَنْ أَعَانَ عَلَى خُصُومَةٍ بِظُلْمٍ فَقَدْ بَاءَ بِغَضَبٍ مِنَ اللَّهِ ﷻ