Muwatta Imam Malik (Riwayat Ibn al-Qasim)

It is narrated from Sayyiduna Abu Hurairah (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "When a Muslim or a believing servant performs ablution, then the sins committed by his eyes (by looking) come out from his face with the water or with the last drop of water," or he (peace be upon him) said something similar. "Then when he washes both his hands, the sins committed by his hands come out with the water or with the last drop of water. Then when he washes both his feet, the sins committed by his feet come out with the water or with the last drop of water, until he emerges completely purified from sins."