Sahih Muslim 544
صحيح مسلم#544SahihHumran, the freed slave of 'Uthman reported:I brought for Uthman b. 'Affan the ablution water. He performed ablution and then said: Verily the people narrate from the Messenger of Allah (ﷺ) a hadith. I do not know what these are. but (I know this fact) that I saw the Messenger of Allah (ﷺ) perform ablution like this ablution of mine and then he said: He who performed ablution like this, all his previous sins would be expiated and his prayer and going towards the mosque would have an extra reward. In the tradition narrated by Ibn 'Abda (the words are):" I came to Uthman and he performed ablution
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Every narration in Sahih Muslim is accepted as Sahih (authentic) by the established status of the book.
In-book reference: 2:11