In short: A thirsty man drank from a well, then saw a dog so thirsty it was licking mud. He climbed back down, filled his shoe with water, held it in his teeth as he climbed up, and gave the dog a drink. Allah thanked him and forgave him (Sahih al-Bukhari 2363).
The story
The Prophet ﷺ told of a man walking on a journey who became very thirsty. He found a well, climbed down and drank. When he came out, he saw a dog panting and eating wet earth from thirst. He thought: this dog is suffering what I was suffering.
So he went back down, filled his leather shoe with water, gripped it in his mouth to climb up, and gave the dog water. Allah appreciated what he did and forgave him. The Companions asked whether there is reward even in caring for animals. He ﷺ said yes: there is reward in caring for every living creature (Sahih al-Bukhari 2363, Sahih Muslim 2244).
The Prophet ﷺ also told of a woman who did the same for a dog and was forgiven (Sahih al-Bukhari 3467).
What we can take from it
- Never think a good deed is too small.
- Your own pain can teach you someone else’s. He helped because he had just felt the same thirst.
- Mercy to animals is worship.