كتاب التوبة
50  
The Book of Repentance
(4)
Chapter: The Vastaess Of Allah's Mercy, Which Prevails Over His Wrath
(4)
باب فِي سَعَةِ رَحْمَةِ اللَّهِ تَعَالَى وَأَنَّهَا سَبَقَتْ غَضَبَهُ ‏‏
Sahih Muslim 2752 a

Abu Huraira reported:

I heard Allah's Messenger (ﷺ) as saying: Allah created mercy in one hundred parts and He retained with Him ninety-nine parts, and He has sent down upon the earth one part, and it is because of this one part that there is mutual love among the creation so much so that the animal lifts up its hoof from its young one, fearing that it might harm it.
حَدَّثَنَا حَرْمَلَةُ بْنُ يَحْيَى التُّجِيبِيُّ، أَخْبَرَنَا ابْنُ وَهْبٍ، أَخْبَرَنِي يُونُسُ، عَنِ ابْنِ شِهَابٍ، أَنَّ سَعِيدَ بْنَ الْمُسَيَّبِ، أَخْبَرَهُ أَنَّ أَبَا هُرَيْرَةَ قَالَ سَمِعْتُ رَسُولَ اللَّهِ صلى الله عليه وسلم يَقُولُ ‏ "‏ جَعَلَ اللَّهُ الرَّحْمَةَ مِائَةَ جُزْءٍ فَأَمْسَكَ عِنْدَهُ تِسْعَةً وَتِسْعِينَ وَأَنْزَلَ فِي الأَرْضِ جُزْءًا وَاحِدًا فَمِنْ ذَلِكَ الْجُزْءِ تَتَرَاحَمُ الْخَلاَئِقُ حَتَّى تَرْفَعَ الدَّابَّةُ حَافِرَهَا عَنْ وَلَدِهَا خَشْيَةَ أَنْ تُصِيبَهُ ‏"‏ ‏.‏
Reference : Sahih Muslim 2752a
In-book reference : Book 50, Hadith 20
USC-MSA web (English) reference : Book 37, Hadith 6629
  (deprecated numbering scheme)