أَ رَأَيْتُمْ لَوْ أَنَّ نَهْراً بِبَابِ أَحَدِكُمْ يَغْتَسِلُ مِنْهُ
كُلَّ يَوْم خَمْسَة مَرَّات، هَلْ يَبْقَى مِنْ دَرَنِهِ شَيْءٌ؟
The Prophet (sallallahu alayhe wa sallam) said: “Do you think, if there were a river in front of the door of one of you (i.e. in front of his house), and he bathed in it five times every day, that there would remain any dirt on him?”
قَالُوا لا يَبْقَى مِنْ دَرَنِهِ شَيْءٌ
The Companions replied: “There would not remain any dirt on him.”
قَالَ فَذَلِكَ مَثَلُ الصَلَوَات الخَمْس، يَمْحُو اللهُ بِهِنَّ الخَطَايَا
The Prophet (sallallahu alayhe wa sallam) said: “That is the example of the five obligatory prayers, God erases the sins with them.”
مَصْدَرُ الحَدِيْث صَحِيْحُ المُسْلِم
from Saheeh Muslim
Find a hadeeth: http://dorar.net/enc/hadith/