Sahih Muslim 1744
صحيح مسلم#1744SahihA'isha reported that when the Messenger of Allah (ﷺ) decided upon doing any act, he continued to do it, and when he slept at night or fell sick he observed twelve rak'ahs during the daytime. I am not aware of Allah's Messenger (ﷺ) observing prayer during the whole of the night till morning, or observing fast for a whole month continuously except that 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: 6:173