Sahih Muslim
The Book on Salutations and Greetings (Kitab As-Salam)
Book Number: 026 / Hadith Number: 5579
Abu Huraira reported Allah's Messenger (may peace be upon him) as saying: There was a dog moving around a well whom thirst would have killed. Suddenly a prostitute from the prostitutes of Bani Isra'il happened to see it and she drew water in her shoe and made it drink, and she was pardoned because of this.