Mustadrak al-Hakim — Hadith 459

It is narrated from Sayyiduna Amr bin Abasah (may Allah be pleased with him) that Abu Ubayd said to him: "Narrate to us a hadith that you heard from the Messenger of Allah (peace and blessings be upon him)." He said: I heard the Messenger of Allah (peace and blessings be upon him) not once, not twice, but more than three times, saying: "When a believing servant performs ablution, rinses his mouth and cleans his nose, the sins fall away from the edges of his mouth; when he washes his hands, the sins fall away from his nails; when he wipes his head, the sins fall away from the edges of his head; then if he stands and prays two rak'ahs, keeping his heart and his gaze fully turned towards Allah, he comes out of his sins as pure as if his mother had given birth to him that very day."
This hadith is sahih (authentic) on the condition of the two Shaykhs (Bukhari and Muslim), but they did not record it. Abu Ubayd is an early Tabi'i whose hearing from Amr bin Abasah is established.