Anas 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

Abu Qilaba reported on the authority of Anas:It is the Sunnah to stay with a virgin (after having married her) for a week. Khalid (one of the narrators) said: If wish I can say that it can be traced up to the Prophet (ﷺ)