Sayyiduna Suraqah bin Malik (may Allah be pleased with him) said: I went to the Messenger of Allah (peace and blessings be upon him) during the illness in which Allah took his (peace and blessings be upon him) soul. I asked him (peace and blessings be upon him) questions, and whatever I asked, he (peace and blessings be upon him) answered me, to the extent that I still remember one of those matters tonight. He said: Among the things I asked him (peace and blessings be upon him) was that I said: "Tell me, if a man fills his trough and stray, roaming or lost camels come to it, will he have a reward for giving them water?" He (peace and blessings be upon him) said: "There is a reward for you in giving water to every creature with a thirsting liver."
Hadith Referenceالمعجم الكبير للطبراني / باب السين / 6568