Humran, the freed slave of Sayyiduna Uthman (may Allah be pleased with him), says: I saw Sayyiduna Uthman bin Affan (may Allah be pleased with him) performing ablution. He poured water from the vessel onto his hands, then washed them three times, then put his right hand into the water, then rinsed his mouth and sniffed water into his nose, then washed his face three times and washed his hands up to and including his elbows, then wiped his head, then washed his right foot three times, then washed his left foot three times. Then he said: I saw the Messenger of Allah (peace and blessings be upon him) performing ablution like this, [and he (peace and blessings be upon him) said:] "Whoever performs ablution like my ablution, then prays two rak'ahs in which no bad thought arises in his heart, his past sins will be forgiven."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 217