صحیح مسلم · Hadith 547

Humran b. Aban reported: I used to fetch water for 'Uthman for his purification. Never was there a day that he did not take a bath with a small quantity of water. And Uthman said: The Messenger of Allah ( ‌صلی ‌اللہ ‌علیہ ‌وسلم ‌ ) at the time of our returning from our prayer told us (certain things pertaining to purification). Mis'ar said: I find that it was afternoon prayer. He said: I do not know whether I should tell you a thing or keep quiet. We said: Messenger of Allah, tell us if it is good and if it is otherwise, Allah and His Apostle know better. Upon this he said: A Muslim who purifies (himself) and completes purification as enjoined upon him by Allah and then offers the prayers, that will be expiation (of his sins he committed) between these (prayers).