A man walking along a path felt very thirsty. Reaching a well, he descended into it, drank his fill, and came up. Then he saw a dog with its tongue hanging out, trying to lick up mud to quench its thirst. The man said,
“This dog is feeling the same thirst that I felt.”
So he went down into the well again, filled his shoe with water, and gave the dog a drink. So, God thanked him and forgave his sins.
The Prophet (Sallallaahu `alayhi wa sallam) was asked,
“Messenger of God, are we rewarded for kindness towards animals?”
“There is a reward for kindness to every living animal or human.”
Narrated in Saheeh Muslim, #2244, and Saheeh Al-Bukhari, #2466.