Sunan an-Nasa'i 5401
It was narrated from Umm Salamah that:
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. If I pass judgment in favor of one of you, against his brother's rights, let him not take it, for it is a piece of fire that I am giving him."
أَخْبَرَنَا عَمْرُو بْنُ عَلِيٍّ، قَالَ حَدَّثَنَا يَحْيَى، قَالَ حَدَّثَنَا هِشَامُ بْنُ عُرْوَةَ، قَالَ حَدَّثَنِي أَبِي، عَنْ زَيْنَبَ بِنْتِ أَبِي سَلَمَةَ، عَنْ أُمِّ سَلَمَةَ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَالَ ‏
"‏ إِنَّكُمْ تَخْتَصِمُونَ إِلَىَّ وَإِنَّمَا أَنَا بَشَرٌ وَلَعَلَّ بَعْضَكُمْ أَلْحَنُ بِحُجَّتِهِ مِنْ بَعْضٍ فَمَنْ قَضَيْتُ لَهُ مِنْ حَقِّ أَخِيهِ شَيْئًا فَلاَ يَأْخُذْهُ فَإِنَّمَا أَقْطَعُهُ بِهِ قِطْعَةً مِنَ النَّارِ ‏"‏ ‏.‏