Abu Juhayfa reported,
We asked Ali 
, "Do you possess anything from the Messenger of Allah ﷺ beyond the Quran?"He replied, "No, by the One who split the seed and created the soul, except for an understanding which Allah 
grants to a man concerning the Quran, and what is in this document."I asked, "What is in the document?"He said, "The rulings on blood-money, the ransoming of captives, and that no Muslim is to be killed in retaliation for a disbeliever."
Ahmad 599
Sahihحدثنا سفيان عن مطرف عن الشعبي
عن أبي جحيفة قال
سألنا عليا رضي الله عنه هل عندكم من رسول الله ﷺ شيء بعد القرآن قال لا والذي فلق الحبة وبرأ النسمة إلا فهم يؤتيه الله عز وجل رجلا في القرآن أو ما في الصحيفة قلت وما في الصحيفة قال العقل وفكاك الأسير ولا يقتل مسلم بكافر
Its isnad is sahih. Mutarrif is Ibn Tarif Harithi. Abu Juhayfa is Wahb bin Abdullah Suwai, with the sin having a damma and the waw unshaddaded, and it was Ali who named him Wahb al-Khayr. Al-aql means blood money. Al-fikak, with either fatha or kasra on the fa, means that by which something is redeemed.The hadith was narrated by Bukhari twice, through the route of Sufyan Ibn Uyayna, (12) 217, 230 of Fath al-Bari, and in Al-Muntaqa 3906 it states that it was also narrated by Abu Dawud, Tirmidhi, and Nasai.As for "illa fahmun," it is established with the raf case in all three manuscript copies, while in Bukhari it appears as "illa fahman" with the nasb case, and this is another reading confirmed in the Musnad in copy K. For this reason, we have recorded both readings. See also 615, 782, 959.