Sahih Muslim 2782
صحيح مسلم#2782SahihA'isha (Allah be pleased with her) reported that the Messenger of Allah (ﷺ) used to observe i'tikaf in the last ten days of Ramadan
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: 14:3