Musannaf Ibn Abi Shayba 18:747

Abu Bakr narrated to us, he said: Ibn 'Uyaynah narrated to us, from Mutarrif, from al-Sha'bi, from Abu Juhayfah, who said: We said to Ali, "Do you have anything from the Messenger of Allah, may Allah bless him and grant him peace, other than the Qur'an?" He said, "No, by the One who split the grain and created the soul, except for an understanding that Allah gives to a man regarding the Book of Allah, and what is in this scroll." I said, "And what is in this scroll?" He said, "The *'aql* (blood money/indemnity), the freeing of the captive, and that a Muslim shall not be killed for a disbeliever."