Language:
كتاب الأحكام
93  
Judgments (Ahkaam)
(29)
Chapter: Whoever is given the right of his brother through a judicial decision
(29)
بَابُ مَنْ قُضِيَ لَهُ بِحَقِّ أَخِيهِ فَلاَ يَأْخُذْهُ، فَإِنَّ قَضَاءَ الْحَاكِمِ لاَ يُحِلُّ حَرَامًا وَلاَ يُحَرِّمُ حَلاَلاً
Sahih al-Bukhari 7181

Narrated Um Salama:

(the wife of the Prophet) Allah's Messenger (ﷺ) heard some people quarreling at the door of his dwelling, so he went out to them and said, "I am only a human being, and litigants with cases of dispute come to me, and someone of you may happen to be more eloquent (in presenting his case) than the other, whereby I may consider that he is truthful and pass a judgment in his favor. If ever I pass a judgment in favor of somebody whereby he takes a Muslim's right unjustly, then whatever he takes is nothing but a piece of Fire, and it is up to him to take or leave."

حَدَّثَنَا عَبْدُ الْعَزِيزِ بْنُ عَبْدِ اللَّهِ، حَدَّثَنَا إِبْرَاهِيمُ بْنُ سَعْدٍ، عَنْ صَالِحٍ، عَنِ ابْنِ شِهَابٍ، قَالَ أَخْبَرَنِي عُرْوَةُ بْنُ الزُّبَيْرِ، أَنَّ زَيْنَبَ ابْنَةَ أَبِي سَلَمَةَ، أَخْبَرَتْهُ أَنَّ أُمَّ سَلَمَةَ زَوْجَ النَّبِيِّ صلى الله عليه وسلم أَخْبَرَتْهَا عَنْ رَسُولِ اللَّهِ صلى الله عليه وسلم أَنَّهُ سَمِعَ خُصُومَةً بِبَابِ حُجْرَتِهِ فَخَرَجَ إِلَيْهِمْ فَقَالَ ‏ "‏ إِنَّمَا أَنَا بَشَرٌ، وَإِنَّهُ يَأْتِينِي الْخَصْمُ، فَلَعَلَّ بَعْضَكُمْ أَنْ يَكُونَ أَبْلَغَ مِنْ بَعْضٍ، فَأَحْسِبُ أَنَّهُ صَادِقٌ فَأَقْضِي لَهُ بِذَلِكَ، فَمَنْ قَضَيْتُ لَهُ بِحَقِّ مُسْلِمٍ، فَإِنَّمَا هِيَ قِطْعَةٌ مِنَ النَّارِ، فَلْيَأْخُذْهَا أَوْ لِيَتْرُكْهَا ‏"‏‏.‏
Reference : Sahih al-Bukhari 7181
In-book reference : Book 93, Hadith 44
USC-MSA web (English) reference : Vol. 9, Book 89, Hadith 292
  (deprecated numbering scheme)