It is narrated from Sayyiduna Abu Hurayrah (may Allah be pleased with him) that the Prophet (peace and blessings be upon him) said: "When a Muslim or believing servant performs ablution and washes his face, every sin he looked at with his eyes leaves his face with the water, or with the last drop of water. And when he washes his hands, every sin his hands committed leaves his hands with the water, or he said: with the last drop of water. And when he washes his feet, every sin his feet committed leaves his feet with the last drop of water, until he emerges completely purified of sins."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 381