the Fatwa Department Research Committee - chaired by Sheikh `Abd al-Wahhâb al-Turayrî
The evidence from the Sunnah indicates that performing wudû’ and offering prayer are both reasons for our sins to be forgiven.
Regarding wudû’, the Prophet (peace be upon him) said: “When a Muslim worshipper performs wudû’ and washes his face, then every sin that he incurred by what his eyes fell upon comes out from his face with the last drop of water. When he washes his hands, every sin that he incurred by way of his grasp comes out form his hands with the last drop of water. When he washes his feet, every sin that he incurred by way of his walking comes out from his feet with the last drop of water. Ultimately, he comes forth free of sin.” [Sahîh al-Bukhârî (360)]
There is also a hadîth related about prayer.
The Prophet (peace be upon him) said: “The five daily prayers are like a running river at the door of someone’s house. He washes himself in it every day five times”.
Al-Hasan then said, rhetorically: “Would that leave any dirt?” [Sahîh Muslim (1072)]
Source: Islam Today