Sahih al-Bukhari 4612
صحيح البخاري#4612SahihNarrated `Aisha:Whoever tells that Muhammad concealed part of what was revealed to him, is a liar, for Allah says:-- "O Apostle (Muhammad)! Proclaim (the Message) which has been sent down to you from your Lord
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: 65:134