Jami` at-Tirmidhi 582
جامع الترمذي#582Sahihحَدَّثَنَا قُتَيْبَةُ، حَدَّثَنَا حَمَّادُ بْنُ زَيْدٍ، عَنْ مُحَمَّدِ بْنِ زِيَادٍ، وَهُوَ أَبُو الْحَارِثِ الْبَصْرِيُّ ثِقَةٌ عَنْ أَبِي هُرَيْرَةَ، قَالَ قَالَ مُحَمَّدٌ صلى الله عليه وسلم " أَمَا يَخْشَى الَّذِي يَرْفَعُ رَأْسَهُ قَبْلَ الإِمَامِ أَنْ يُحَوِّلَ اللَّهُ رَأْسَهُ رَأْسَ حِمَارٍ " . قَالَ قُتَيْبَةُ قَالَ حَمَّادٌ قَالَ لِي مُحَمَّدُ بْنُ زِيَادٍ وَإِنَّمَا قَالَ " أَمَا يَخْشَى " . قَالَ أَبُو عِيسَى هَذَا حَدِيثٌ حَسَنٌ صَحِيحٌ . وَمُحَمَّدُ بْنُ زِيَادٍ هُوَ بَصْرِيٌّ ثِقَةٌ وَيُكْنَى أَبَا الْحَارِثِ .
Abu Hurairah narrated:"Muhammad said: 'Does not the one who raises his head before the Imam fear that Allah will transform his head into a donkey's head?
Scholarly Authentication
The label above is the grade most of these scholars gave — one dissenting opinion no longer speaks for all of them. If any scholar calls a narration fabricated, that verdict is shown instead, whatever the others say. Each scholar's own wording:
In-book reference: 6:39