Prayer is the link between the servant and his Rabb. It is the rich source from which a person derives strength, steadfastness, mercy and contentment, and it is a means of cleansing the stain of his or her sins:
Abu Hurayrah (RAA) narrated:
“I heard the Messenger of Allah (PBUH) say: `What would you think if there were a river running by the door of any of you, and he bathed in it five times every day, would any trace of dirt be left on him?’ The people said: `There would be no trace of dirt on him.’ He said: `This is like the five daily prayers, through which Allah (SWT) erases sins.'” (Sharh al-Sunnah 2/175)
Jabir (RAA) said:
“The Messenger of Allah (PBUH) said: `The five daily prayers are like a deep river flowing by the door of any of you, in which he bathes five times every day.’“ 
 Reported by Tirmidhi, 4/249, in Anwar al-birr, 70. He said it is a hasan hadith.
 Reported by Bukhari in al-Adab al-Mufrad, 1/375, Bab sakhawak al-nafs