عَنْ أَبِي هُرَيْرَةَ رَضِيَ اللَّهُ عَنْهُ قَالَ: قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ: «غُفِرَ لِامْرَأَةٍ مُومِسَةٍ مَرَّتْ بِكَلْبٍ عَلَى رَأْسِ رَكِيٍّ يَلْهَثُ كَادَ يَقْتُلُهُ الْعَطَشُ فَنَزَعَتْ خُفَّهَا فَأَوْثَقَتْهُ بِخِمَارِهَا فَنَزَعَتْ لَهُ مِنَ الْمَاءِ فَغُفِرَ لَهَا بِذَلِكَ» . قِيلَ: إِنَّ لَنَا فِي الْبَهَائِمِ أَجْرًا؟ قَالَ: «فِي كُلِّ ذَاتِ كبد رطبَة أجر»
Abu Huraira reported God’s messenger as saying,
“Forgiveness was granted to an unchaste woman who coming upon a dog panting and almost dead with thirst at the mouth of a well, took off her shoe, tied it with her head-covering, and drew some water for it. On that account she was forgiven.” He was asked whether people received a reward for what they did to animals, and replied, “A reward is given in connection with every living creature.”*
(Bukhari and Muslim.)
* Literally, everything possessed of a moist liver.