Sahih al-Bukhari 7277
صحيح البخاري#7277SahihNarrated `Abdullah:The best talk (speech) is Allah's Book 'Qur'an), and the best way is the way of Muhammad, and the worst matters are the heresies (those new things which are introduced into the religion); and whatever you have been promised will surely come to pass, and you cannot escape (it)
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: 96:10