Safiyyah was from the safi.
كانت صفية من الصفي.
No references are available.
Abu Dawud (2994) reported it, and Ibn Hibban (4822) and Hakim (2/128, and 3/39) graded it sahih, through routes from Sufyan (that is, Thawri), from Hisham bin Urwa, from his father, from Ayesha, who mentioned it as stated. Its isnad is sahih. Hakim said, "This is a sahih hadith according to the criteria of the two Shaykhs."