Abu Hurairahu (RadhiAllahu 'anhu) reported:
I heard the Messenger of Allah (Sallallaahu 'alaihi
wasallam) saying: "Say, if there were a river at the door of one of you
in which he takes a bath five times a day, would any soiling remain on him?''
They replied, "No soiling would left on him.''
He (Sallallaahu 'alaihi
wasallam) said, '' That is the five (obligatory) Salat (prayers). Allah
obliterates all sins as a result of performing them.''
[Al-Bukhari and Muslim]