Musannaf Ibn Abi Shayba 28:780

'Abd al-Rahim ibn Sulayman narrated to us, from Ash'ath, from Muhammad, who said: The fifth [is for] Allah, and the share of the Prophet (may Allah bless him and grant him peace), and the *safiyy* (choice portion). It used to be chosen for him from the spoils of war: the best head [of livestock or person] from the captives, if there were captives, otherwise something else, after the fifth. Then his share is allotted to him, whether he was present or absent with the Muslims, after the *safiyy*. He said: And he chose Safiyyah bint Huyayy on the day of Khaybar. Ash'ath said: And Abu al-Zubayr, 'Amr ibn Dinar, and al-Zuhri said: The Messenger of Allah (may Allah bless him and grant him peace) chose Dhu al-Fiqar on the day of Badr.