Abu Huraira (RAA)"I heard Rasulullah (SAW) saying, 'If there was
a river at the door of anyone of you and he took a bath in it five times
a day would you notice any dirt on him?' They said, 'Not a trace of dirt
would be left.' The Prophet added, 'That is the example of the five prayers
with which Allah blots out (annuls) evil deeds."
(Sahih Bukhari Volume 1, Hadith # 506)