Sahih al-Bukhari Book 78, Hadith 39
We came to the Prophet (ﷺ) and we were (a few) young men of approximately equal age and stayed with
him for twenty nights. Then he thought that we were anxious for our families, and he asked us whom
we had left behind to look after our families, and we told him. He was kindhearted and merciful, so he
said, "Return to your families and teach them (religious knowledge) and order them (to do good
deeds) and offer your prayers in the way you saw me offering my prayers, and when the stated time
for the prayer becomes due, then one of you should pronounce its call (i.e. the Adhan), and the eldest
of you should lead you in prayer.
Allah's Messenger (ﷺ) said, "The one who looks after and works for a widow and for a poor person is like a warrior fighting for Allah's Cause." (The narrator Al-Qa'nabi is not sure whether he also said "Like the one who prays all the night without slackness and fasts continuously and never breaks his fast.")
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) ."