Sahih al-Bukhari Book 78, Hadith 41
Allah's Messenger (ﷺ) stood up for the prayer and we too stood up along with him. Then a bedouin shouted
while offering prayer. "O Allah! Bestow Your Mercy on me and Muhammad only and do not bestow
it on anybody else along with us." When the Prophet (ﷺ) had finished his prayer with Taslim, he said to
the Bedouin, "You have limited (narrowed) a very vast (thing)," meaning Allah's Mercy.
Allah's Messenger (ﷺ) said, "While a man was walking on a road. he became very thirsty. Then he came across a well, got down into it, drank (of its water) and then came out. Meanwhile he saw a dog panting and licking mud because of excessive thirst. The man said to himself "This dog is suffering from the same state of thirst as I did." So he went down the well (again) and filled his shoe (with water) and held it in his mouth and watered the dog. Allah thanked him for that deed and forgave him." The people asked, "O Allah's Messenger (ﷺ)! Is there a reward for us in serving the animals?" He said, "(Yes) There is a reward for serving any animate (living being) ."
Allah's Messenger (ﷺ) said, "You see the believers as regards their being merciful among themselves and showing love among themselves and being kind, resembling one body, so that, if any part of the body is not well then the whole body shares the sleeplessness (insomnia) and fever with it."