The Book of Repentance
Ṣaḥīḥ Muslim 6977
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
inna-Llāh khalaqa yawma khalaqa as-samawāti wa-l-arḍa māʾaha raḥmatin kullu raḥmatin ṭibāqa mā bayna as-samāʾi wa-l-arḍi fajaʿala minhā fī al-arḍi raḥmatan fabihā taʿṭifu al-wālidah ʿalā waladihā wa-l-waḥshu wa-aṭ-ṭayru baʿḍuhā ʿalā baʿḍin fa-idhā kāna yawmu al-qiyāmah akmalahā bihadhihi ar-raḥmah
Transliteration generated from the Arabic vowel marks
The full narration
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)
Source
Ṣaḥīḥ Muslim · 6977