Sunan Abu Dawud
2995
Sahih+3

Anas bin Malik said “We came to Khaibar. We bestowed the conquest of fortress (on us), the beauty of Safiyyah daughter of Huyayy was mentioned to him (the Prophet). Her husband was killed (in the battle) and she was a bride. The Apostle of Allaah(ﷺ) chose her for himself. He came out with her till we reached Sadd Al Sahba’ where she was purified. So he cohabited with her

SahihAl-Albani
SahihMuhammad Muhyi Al-Din Abdul Hamid