بسم الله الرحمن الرحيم
Abu Huraira narrated the statement of Allah’s Messenger -sallahu alayhi wa sallam-, “While a man was walking on a road he was stricken with severe thirst. He stumbled upon a well and descended therein, consequently drinking (until his thirst was quenched) and then exited it. Meanwhile he saw a dog panting and licking mud due to thirst. As a result the man said, ‘Thirst has affected this dog like that which affected me.’ So he descended into the well and filled his footwear with water, grasping it by his mouth, then he gave it water to drink. Consequently Allah thanked and forgave him.” They (those present) said, “O Messenger of Allah! Is there reward for us as a result of animals? He -sallahu alayhi wa sallam- said, “In every sentient being/creature there is a reward.” Collected by Al Bukhari and Muslim.
Sheikh Zayd Al Madkhali said, “This narration is a proof for the obligation of mercy towards animals and occasionally it is highly recommended. As the story in which a man saw a dog, and the dog is the least of animals in value, being that it was panting out of thirst he climbed down into a well in order to give it water. Consequently this became a means for receiving Allah’s mercy and thanks and He forgave him for his sins. In another chain of transmission there is a woman prostitute in which the same thing transpired with her, thus she was forgiven as well.
Therefore the narration therein is a clarification with regards to livestock owned by man, that he is responsible for them and they are from his herd (that which is placed under his care or custody). Thus it is mandatory to establish what is binding for them from food and drink, and having the concern that is befitting in that regard. If he does that for him is reward, but if he neglects that upon him is sin. In fact, when the Prophet -sallahu alayhi wa sallam- was asked about giving food or drink to animals he responded by saying, ‘In every sentient being/creature there is a reward.’ Along with the differing in species of created beings, everything man feeds or waters is included and there is for him a reward despite the different species. Whether it is livestock/cattle or animals that pass by your homes like cats and dogs, in all of them is reward.
So a man intends and expects that whatever is consumed from his money or substances of his drunken therein is reward.”
Translated by Najeeb Al Anjelesi
Source: عون الأحد الصمد شرح الأدب المفرد