Sahih Muslim 3626
صحيح مسلم#3626SahihAnas b. Malik reported:When anyone who has already a wife marries virgin, he should stay with her for seven nights (and then turn to his other wife), but when anyone having a virgin with him (as his wife) marries a woman who has been previously married he should stay with her for three nights. Khalid (one of the narrators) said. If I were to say that it could be directly traced to the Prophet (ﷺ). I would have told the truth, but he (Hadrat Anas) said: Such is the tradition
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: 17:59