Sahih Bukhari Volume 9, Book 93, Hadith 7187

حَدَّثَنَا أَبُو الْيَمَانِ، أَخْبَرَنَا شُعَيْبٌ، عَنِ الزُّهْرِيِّ، أَخْبَرَنِي عُرْوَةُ بْنُ الزُّبَيْرِ، أَنَّ زَيْنَبَ بِنْتَ أَبِي سَلَمَةَ، أَخْبَرَتْهُ عَنْ أُمِّهَا أُمِّ سَلَمَةَ، قَالَتْ سَمِعَ النَّبِيُّ صلى الله عليه وسلم جَلَبَةَ خِصَامٍ عِنْدَ بَابِهِ فَخَرَجَ عَلَيْهِمْ فَقَالَ ‏"‏ إِنَّمَا أَنَا بَشَرٌ، وَإِنَّهُ يَأْتِينِي الْخَصْمُ، فَلَعَلَّ بَعْضًا أَنْ يَكُونَ أَبْلَغَ مِنْ بَعْضٍ، أَقْضِي لَهُ بِذَلِكَ وَأَحْسِبُ أَنَّهُ صَادِقٌ، فَمَنْ قَضَيْتُ لَهُ بِحَقِّ مُسْلِمٍ فَإِنَّمَا هِيَ قِطْعَةٌ مِنَ النَّارِ، فَلْيَأْخُذْهَا أَوْ لِيَدَعْهَا ‏"

Narrated By Um Salama : The Prophet heard the voices of some people quarrelling near his gate, so he went to them and said, "I am only a human being and litigants with cases of disputes come to me, and maybe one of them presents his case eloquently in a more convincing and impressive way than the other, and I give my verdict in his favour thinking he is truthful. So if I give a Muslim's right to another (by mistake), then that (property) is a piece of Fire, which is up to him to take it or leave it."