Sunan an Nasai
3381
Sahih+2

It was narrated from Humaid that he heard Anas say:"The Messenger of Allah stayed with Safiyyah bint Huyayy bin Akhtab on the way (back from) Khaibar for three days when he married her, then she was among those who were commanded to observe Hijab

SahihAbu Ghuddah
SahihAl-Albani