Sahih al-Bukhari 887
صحيح البخاري#887SahihNarrated Abu Huraira:Allah's Messenger (ﷺ) said, "If I had not found it hard for my followers or the people, I would have ordered them to clean their teeth with Siwak for every prayer
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Every narration in Sahih al-Bukhari is accepted as Sahih (authentic) by the established status of the book.
In-book reference: 11:12