Sunan Ibn Majah, Chapter: The Chapters of Purification and its Sunnah

that the Messenger of Allah (saw) said: "Whoever performs ablution and rinses his mouth and nose, his sins will exit through his mouth and nose. When he washes his face, his sins will exit from his face, even from beneath his eyelids. When he washes his hands, his sins will exit from his hands. When he wipes his head, his sin will exit from his head, and even from his ears. When he washes his feet, his sins will exit from his feet, even from beneath his toenails. Then his prayer and his walking towards the mosque will earn extra merit for him." (Sahih)