Sahih Muslim 2767
صحيح مسلم#2767SahihIbn 'Umar (Allah be pleased with both of them) reported Allah's Messenger (ﷺ) as saying:Seek the time of Lailat-ul-Qadr in the last (ten nights), or he said: in the last nine (nights)
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: 13:273