Aban bin `Uthman said:
‘Uthman said: I heard the Messenger of Allah (ﷺ) say: “Do you think if there was a river in the courtyard of one of you and he washed himself in it five times each day, would any dirt remain on him? They said: Nothing [would remain on him). He said: `The (five daily) prayers take away sins as water takes away dirt.`