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.
tabarani:12666ʿAbdullāh b. Muḥammad b. Saʿīd b. Abū Maryam > Muḥammad b. Yūsuf al-Firyābī > Qays b. al-Rabīʿ > al-Aghar b. al-Ṣabbāḥ > Khalīfah b. Ḥuṣayn > Abū Naṣr > Ibn ʿAbbās

[Machine] "The Aws and Khazraj tribes were at odds with each other during the time of ignorance. One day, while they were sitting together, they started mentioning the past disputes between them, which made them angry. Some of them even picked up weapons and got ready to fight. Then the following verse was revealed: 'And how is it that you disbelieve, while the verses of Allah are recited to you and among you is His Messenger?' The entire verse and the two verses that came after it, including 'And remember the favor of Allah upon you when you were enemies and He brought your hearts together'."  

الطبراني:١٢٦٦٦حَدَّثَنَا عَبْدُ اللهِ بْنُ مُحَمَّدِ بْنِ سَعِيدِ بْنِ أَبِي مَرْيَمَ ثنا مُحَمَّدُ بْنُ يُوسُفَ الْفِرْيَابِيُّ ثنا قَيْسُ بْنُ الرَّبِيعِ عَنِ الْأَغَرِّ بْنِ الصَّبَّاحِ عَنْ خَلِيفَةَ بْنِ حُصَيْنٍ عَنْ أَبِي نَصْرٍ عَنِ ابْنِ عَبَّاسٍ قَالَ

«كَانَتِ الْأَوْسُ وَالْخَزْرَجُ فِي الْجَاهِلِيَّةِ بَيْنَهُمْ شَرٌّ فَبَيْنَمَا هُمْ يَوْمًا جُلُوسٌ ذَكَرُوا مَا بَيْنَهُمْ حَتَّى غَضِبُوا فَقَامَ بَعْضُهُمْ إِلَى بَعْضٍ بِالسِّلَاحِ» فَنَزَلَتْ {وَكَيْفَ تَكْفُرُونَ وَأَنْتُمْ تُتْلَى عَلَيْكُمْ آيَاتُ اللهِ وَفِيكُمْ رَسُولُهُ} الْآيَةُ كُلُّهَا وَالْآيَتَانِ بَعْدَهَا إِلَى {وَاذْكُرُوا نِعْمَةَ اللهِ عَلَيْكُمْ إِذْ كُنْتُمْ أَعْدَاءً فَأَلَّفَ بَيْنَ قُلُوبِكُمْ}