Sahih Muslim 549
صحيح مسلم#549SahihHumran, the freed slave of 'Uthman b. 'Affan, reported on the authority of 'Uthman b. 'Affan that he heard Allah's Messenger (ﷺ) say:He who performed ablution for prayer and performed it properly and then went (to observe) obligatory prayer and offered it along with people or with the congregation or in the mosque, Allah would pardon his sins
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: 2:16