Sahih Bukhari Volume 3, Book 46, Hadith 2459

حَدَّثَنَا عَبْدُ الْعَزِيزِ بْنُ عَبْدِ اللَّهِ، قَالَ حَدَّثَنِي إِبْرَاهِيمُ بْنُ سَعْدٍ، عَنْ صَالِحٍ، عَنِ ابْنِ شِهَابٍ، قَالَ أَخْبَرَنِي عُرْوَةُ بْنُ الزُّبَيْرِ، أَنَّ زَيْنَبَ بِنْتَ أُمِّ سَلَمَةَ، أَخْبَرَتْهُ أَنَّ أُمَّهَا أُمَّ سَلَمَةَ ـ رضى الله عنها ـ 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 صَدَقَ، فَأَقْضِيَ لَهُ بِذَلِكَ، فَمَنْ قَضَيْتُ لَهُ بِحَقِّ مُسْلِمٍ فَإِنَّمَا هِيَ قِطْعَةٌ مِنَ النَّارِ، فَلْيَأْخُذْهَا أَوْ فَلْيَتْرُكْهَا ‏"‏‏.‏

Narrated By Um Salama : (The wife of the Prophet) Allah's Apostle heard some people quarrelling at the door of his dwelling. He came out and said, "I am only a human being, and opponents come to me (to settle their problems); maybe someone amongst you can present his case more eloquently than the other, whereby I may consider him true and give a verdict in his favour. So, If I give the right of a Muslim to another by mistake, then it is really a portion of (Hell) Fire, he has the option to take or give up (before the Day of Resurrection)."