Sahih al-Bukhari 790
صحيح البخاري#790SahihNarrated Mus`ab bin Sa`d:I offered prayer beside my father and approximated both my hands and placed them in between the knees. My father told me not to do so and said, "We used to do the same but we were forbidden (by the Prophet) to do it and were ordered to place the hands on the knees
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: 10:185