Musnad Abu Ya'la al-Mawsili 129:117

Ibrahim ibn Sa'id al-Jawhari narrated to us, Abu al-Nadr narrated to us, Abu Ja'far al-Razi narrated to us, from Humayd, from Anas: The Prophet, peace and blessings of Allah be upon him, married Safiyyah and made her manumission her dowry. He made the wedding feast three days long. He spread out a leather mat that Umm Sulaym had brought, and he placed dried yogurt and dates upon it, and he fed the people for three days.