Al-Adab Al-Mufrad: Mercy – Hadith No. 380 — The Messenger of Allah, may Allah bless him and grant him peace, said, “One day… (Hadith No. 380)

Abu Hurayra reported that the Messenger of Allah, may Allah bless
him and grant him peace, said, "One day a man became very thirsty while
walking down the road. He came across a well, went down into it, and drank
and then climbed out. In front of him he found a dog panting, eating the
dust out of thirst. The man said, 'This dog is as thirsty as I was.' He
went back down into the well and filled his shoe, putting it into his mouth
(in order to climb back up) and then gave the dog water. Therefore Allah
thanked him and forgave him." They said, "Messenger of Allah, will we have
a reward on account of animals?" He said, "There is a reward on account
of every living thing."

Explanation:

Reference: Al-Adab Al-Mufrad, Mercy, Hadith No. 380