Sahih al-Bukhari, Volume 9, Book 92, Hadith 383 (USC-MSA) ⓘ
Narrated Abu Huraira and Zaid bin Khalid: We were with the Prophet when he said (to two men), "I shall judge between you according to Allah's Book (Laws)."
حَدَّثَنَا مُسَدَّدٌ، حَدَّثَنَا سُفْيَانُ، حَدَّثَنَا الزُّهْرِيُّ، عَنْ عُبَيْدِ اللَّهِ، عَنْ أَبِي هُرَيْرَةَ، وَزَيْدِ بْنِ خَالِدٍ، قَالاَ كُنَّا عِنْدَ النَّبِيِّ صلى الله عليه وسلم فَقَالَ " لأَقْضِيَنَّ بَيْنَكُمَا بِكِتَابِ اللَّهِ " .
also referenced under: Book 96, Hadith 11 (In-Book) & Hadith 7278 (DarusSalam)