Sunan an-Nasai Book 49, Hadith 5422

أَخْبَرَنَا إِسْحَاقُ بْنُ إِبْرَاهِيمَ، قَالَ حَدَّثَنَا وَكِيعٌ، عَنْ هِشَامِ بْنِ عُرْوَةَ، عَنْ أَبِيهِ، عَنْ زَيْنَبَ بِنْتِ أُمِّ سَلَمَةَ، عَنْ أُمِّ سَلَمَةَ، قَالَتْ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم ‏ "‏ إِنَّكُمْ تَخْتَصِمُونَ إِلَىَّ وَإِنَّمَا أَنَا بَشَرٌ وَلَعَلَّ بَعْضَكُمْ أَلْحَنُ بِحُجَّتِهِ مِنْ بَعْضٍ فَإِنَّمَا أَقْضِي بَيْنَكُمَا عَلَى نَحْوِ مَا أَسْمَعُ فَمَنْ قَضَيْتُ لَهُ مِنْ حَقِّ أَخِيهِ شَيْئًا فَإِنَّمَا أَقْطَعُ لَهُ قِطْعَةً مِنَ النَّارِ ‏"‏ ‏.‏

It was narrated that Umm Salamah said:"The Messenger of Allah [SAW] said: 'You refer your disputes to me, but I am only human. And some of you may be more eloquent in arguing their case than others, and I may pass judgment on the basis of what I hear. If I pass judgment in favor of one of you against his brother's rights, then it is a piece of the fire that I am giving him