Al-Adab Al-Mufrad, Book 20, Hadith 381 (English) ⓘ
Abu Umama that the Messenger of Allah, may Allah bless him and grant him peace, said, "Anyone who shows mercy, even to an animal meant for slaughtering, will be shown mercy by Allah on the Day of Rising."
حَدَّثَنَا مَحْمُودٌ، قَالَ: حَدَّثَنَا يَزِيدُ، قَالَ: أَخْبَرَنَا الْوَلِيدُ بْنُ جَمِيلٍ الْكِنْدِيُّ، عَنِ الْقَاسِمِ بْنِ عَبْدِ الرَّحْمَنِ، عَنْ أَبِي أُمَامَةَ قَالَ: قَالَ رَسُولُ اللهِ صلى الله عليه وسلم: مَنْ رَحِمَ وَلَوْ ذَبِيحَةً، رَحِمَهُ اللَّهُ يَوْمَ الْقِيَامَةِ.
also referenced under: Hadith 381 (Reference) & Book 20, Hadith 10 (In-Book)