Al-Imām al-Bukhārī narrates: Muḥammad ibn Salām narrated to us; he said: Wakī’ informed us, from Sufyān, from Muṭarrif, from al-Sha’bī,
from Abū Juḥayfah, who said: I asked ‘Alī (may Allāh Almighty be content with him): “Do you have anything written down?” He replied: “Nothing except the Book of Allāh, or understanding that is granted to a Muslim, or what is written on this parchment.” I asked: “What is written on this parchment?” He said: “The rulings concerning blood-money, the ransoming of captives, and that a Muslim is not to be killed in retaliation for a disbeliever (a belligerent non-Muslim).”
Reference: Sahih Al Bukhari 111