I heard Messenger of Allah ﷺ 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 ﷺ added, "That is the example of the five prayers with which Allah blots out (annuls) evil deeds."  

أَنَّهُ سَمِعَ رَسُولَ اللَّهِ ﷺ يَقُولُ أَرَأَيْتُمْ لَوْ أَنَّ نَهَرًا بِبَابِ أَحَدِكُمْ يَغْتَسِلُ فِيهِ كُلَّ يَوْمٍ خَمْسًا مَا تَقُولُ ذَلِكَ يُبْقِي مِنْ دَرَنِهِ قَالُوا لاَ يُبْقِي مِنْ دَرَنِهِ شَيْئًا قَالَ فَذَلِكَ مِثْلُ الصَّلَوَاتِ الْخَمْسِ يَمْحُو اللَّهُ بِهَا الْخَطَايَا