Mustadrak al-Hakim — Hadith 451

It is narrated from Sayyiduna Abdullah al-Sunabihi (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "When the servant performs ablution and rinses his mouth, the (minor) sins leave his mouth; when he puts water into his nose and blows it out, the sins leave his nose; when he washes his face, the sins leave his face, until they leave even from beneath his eyelashes. When he washes his hands, the sins leave his hands, until they leave even from beneath the nails of his hands. When he wipes his head, the sins leave his head, until they leave even from his ears; and when he washes his feet, the sins leave his feet, until they leave even from beneath the nails of his feet. Then his walking to the mosque and his prayer become supererogatory (extra reward) for him."
This hadith is sahih (authentic) on the condition of the two Shaykhs (Bukhari and Muslim), but they did not record it, and there is no hidden defect ('illah) in it. They recorded part of this text from the hadith of Uthman and Abu Hurayrah (may Allah be pleased with them both), but not in full. Abdullah al-Sunabihi is a well-known Companion.