Sahih Muslim 2753 c
Salman reported that Allah's Messenger (ﷺ) said:
Verily, Allah created, on the same very day when He created the heavens and the earth, one hundred parts of mercy. Every part of mercy is coextensive with the space between the heavens. and the earth and He out of this mercy endowed one part to the earth and it is because of this that the mother shows affection to her child and even the beasts and birds show kindness to one another and when there would be the Day of Resurrection, Allah would make full (use of Mercy).
حَدَّثَنَا ابْنُ نُمَيْرٍ، حَدَّثَنَا أَبُو مُعَاوِيَةَ، عَنْ دَاوُدَ بْنِ أَبِي هِنْدٍ، عَنْ أَبِي عُثْمَانَ، عَنْ 
 سَلْمَانَ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم ‏
"‏ إِنَّ اللَّهَ خَلَقَ يَوْمَ خَلَقَ السَّمَوَاتِ وَالأَرْضَ
 مِائَةَ رَحْمَةٍ كُلُّ رَحْمَةٍ طِبَاقَ مَا بَيْنَ السَّمَاءِ وَالأَرْضِ فَجَعَلَ مِنْهَا فِي الأَرْضِ رَحْمَةً فَبِهَا
 تَعْطِفُ الْوَالِدَةُ عَلَى وَلَدِهَا وَالْوَحْشُ وَالطَّيْرُ بَعْضُهَا عَلَى بَعْضٍ فَإِذَا كَانَ يَوْمُ الْقِيَامَةِ أَكْمَلَهَا
 بِهَذِهِ الرَّحْمَةِ ‏"‏ ‏.‏