Abu Hurairah reported the Apostle of Allaah ﷺ as saying “ While a man was going on his way, he felt himself thirsty severely. He found a well and e went down in it. He drank water and came out. Suddenly he saw a dog panting and eating soil due to thirst. The man said (to himself) “This dog must have reached the same condition due to thirst as I had reached. So he went down into the well, filled his sock with water, held it with his mouth and came up. He supplied water to the dog. Allaah appreciated this and forgave him.” They asked “Apostle of Allaah ﷺ, Is there any reward for us for these beasts? He replied, For every cool liver there is a reward.” (Using translation from Abū Dāʾūd 2550)
أَنَّ رَسُولَ اللهِ ﷺ قَالَ بَيْنَمَا رَجُلٌ يَمْشِي بِطَرِيقٍ اشْتَدَّ عَلَيْهِ الْعَطَشُ فَوَجَدَ بِئْرًا فَنَزَلَ فِيهَا فَشَرِبَ ثُمَّ خَرَجَ فَإِذَا كَلْبٌ يَلْهَثُ يَأْكُلُ الثَّرَى مِنَ الْعَطَشِ فَقَالَ الرَّجُلُ لَقَدْ بَلَغَ هَذَا الْكَلْبَ مِنَ الْعَطَشِ مِثْلُ الَّذِي بَلَغَنِي فَنَزَلَ الْبِئْرَ فَمَلَأَ خُفَّهُ ثُمَّ أَمْسَكَهُ بِفِيهِ حَتَّى رَقِيَ فَسَقَى الْكَلْبَ فَشَكَرَ اللهُ لَهُ فَغَفَرَ لَهُ قَالُوا يَا رَسُولَ اللهِ وَإِنَّ لَنَا فِي الْبَهَائِمِ أَجْرًا؟ فَقَالَ فِي كُلِّ ذَاتِ كَبِدٍ رَطْبَةٍ أَجْرٌ