Sahih Muslim 721
صحيح مسلم#721SahihUrwa has narrated it on the authority of 'A'isha that when Allah's Messenger (ﷺ) took a bath because of sexual intercourse, he first washed his hands before dipping one of them into the basin, and then performed ablu- tion as is done for prayer
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: 3:43