Sahih Muslim 1307
صحيح مسلم#1307SahihAbdullah b. Zubair narrated on the authority of his father:When the Messenger of Allah (ﷺ) sat in prayer. he placed the left foot between his thigh and shank and stretched the right foot and placed his left hand on his left knee and placed his right hand on his right thigh, and raised his finger
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: 5:145