Narrated Abu Huraira:The Prophet (ﷺ) was asked about donkeys and he replied, "Nothing has been revealed to me regarding donkeys except this comprehensive Verse which includes everything: "So whoever does good equal to the weight of an atom (or a smallest ant) shall see it; And whoever, does evil equal to the weight of an atom or a smallest ant) shall see it.' (99.7-8)
حَدَّثَنَا يَحْيَى بْنُ سُلَيْمَانَ، قَالَ حَدَّثَنِي ابْنُ وَهْبٍ، قَالَ أَخْبَرَنِي مَالِكٌ، عَنْ زَيْدِ بْنِ أَسْلَمَ، عَنْ أَبِي صَالِحٍ السَّمَّانِ، عَنْ أَبِي هُرَيْرَةَ، رضى الله عنه سُئِلَ النَّبِيُّ صلى الله عليه وسلم عَنِ الْحُمُرِ فَقَالَ " لَمْ يُنْزَلْ عَلَىَّ فِيهَا شَىْءٌ إِلاَّ هَذِهِ الآيَةُ الْجَامِعَةُ الْفَاذَّةُ {فَمَنْ يَعْمَلْ مِثْقَالَ ذَرَّةٍ خَيْرًا يَرَهُ * وَمَنْ يَعْمَلْ مِثْقَالَ ذَرَّةٍ شَرًّا يَرَهُ}".
Bukhari
Prophetic Commentary on the Qur'an (Tafseer of the Prophet (pbuh)) • Hadith 485