Narrated Abu Hurayrah:
The Prophet (ﷺ) said: People who get up from an assembly in which they did not remember Allah will be just as if they had got up from the carcass of a donkey, and it will be a cause of grief to them.
حَدَّثَنَا مُحَمَّدُ بْنُ الصَّبَّاحِ الْبَزَّازُ، حَدَّثَنَا إِسْمَاعِيلُ بْنُ زَكَرِيَّا، عَنْ سُهَيْلِ بْنِ أَبِي صَالِحٍ، عَنْ أَبِيهِ، عَنْ أَبِي هُرَيْرَةَ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم “ مَا مِنْ قَوْمٍ يَقُومُونَ مِنْ مَجْلِسٍ لاَ يَذْكُرُونَ اللَّهَ فِيهِ إِلاَّ قَامُوا عَنْ مِثْلِ جِيفَةِ حِمَارٍ وَكَانَ لَهُمْ حَسْرَةً ” .
Reference : Sunan Abu Dawud 4855
In-book reference : Book 43, Hadith 83
English translation : Book 42, Hadith 4837