[Machine] Salama, a man from the tribe of Um Salama, reported that Um Salama said, "Zubayr had a dispute with a man and they both brought their case to the Messenger of Allah ﷺ . The Prophet ruled in favor of Zubayr, so the man said, 'He ruled in his favor just because he is his cousin.' Then the verse {But no, by your Lord, they will not [truly] believe until they make you, [O Muhammad], judge concerning that over which they dispute among themselves} was revealed."  

عَنْ سَلَمَةَ رَجُلٍ مِنْ وَلَدِ أُمِّ سَلَمَةَ عَنْ أُمِّ سَلَمَةَ قَالَتْ خَاصَمَ الزُّبَيْرُ رَجُلًا إِلَى رَسُولِ اللهِ ﷺ فَقَضَى لِلزُّبَيْرِ فَقَالَ الرَّجُلُ إِنَّمَا قَضَى لَهُ لِأَنَّهُ ابْنُ عَمَّتِهِ فَنَزَلَتْ {فَلَا وَرَبِّكَ لَا يُؤْمِنُونَ حَتَّى يُحَكِّمُوكَ} الْآيَةَ