Musnad Ahmad 5:38

Sufyan narrated to us, from Mutarrif, from al-Sha'bi, from Abu Juhayfah, who said: We asked 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 Him who split the seed and created the soul, except for an understanding that Allah, the Almighty and Majestic, gives to a man regarding the Qur'an, or what is in the scroll." I said: "And what is in the scroll?" He said: "The [rules of] blood money (al-'aql), the ransoming of the captive, and that a Muslim shall not be killed for a disbeliever."