Majma al-Zawaid — Hadith 1163

Humran bin Aban narrates: I saw Sayyiduna Uthman (may Allah be pleased with him) call for water for ablution while he was at the door of the mosque. He washed both his hands, rinsed his mouth, and put water into his nose. Then he washed his face three times, then washed both his arms up to the elbows three times, then wiped his head and passed his hands over the outer part of his ears, then passed them over his beard. Then he washed both his feet up to the ankles three times. Then he stood and offered two rak'ahs, and then said: I have performed ablution before you just as I saw the Prophet (peace and blessings be upon him) perform ablution, and then I offered two rak'ahs just as I saw the Prophet (peace and blessings be upon him) offer them. When the Prophet (peace and blessings be upon him) finished those two rak'ahs, he (peace and blessings be upon him) said: "Whoever performs ablution as I have performed ablution, and then offers two rak'ahs without becoming lost in his own thoughts during them, the sins between those two rak'ahs and his prayer of the previous day are forgiven for him." (Al-Haythami says:) I say:
Ahmad recorded it; it is in the Sahih in abridged form, and its narrators have been declared trustworthy.