Musnad Abu Ya'la al-Mawsili 115:333

Abu Musa narrated to us, Abd al-A’la narrated to us, Sa’id narrated to us, from Qatadah, from Anas, that the Prophet of Allah (may Allah bless him and grant him peace) emancipated Safiyyah bint Huyayy and made her emancipation her dowry.