(31) باب لاَ يُقْتَلُ الْمُسْلِمُ بِالْكَافِرِ
Narrated Abu Juhaifa:
I asked `Ali "Do you have anything Divine literature besides what is in the Qur'an?" Or, as Uyaina once said, "Apart from what the people have?" `Ali said, "By Him Who made the grain split (germinate) and created the soul, we have nothing except what is in the Qur'an and the ability (gift) of understanding Allah's Book which He may endow a man, with and what is written in this sheet of paper." I asked, "What is on this paper?" He replied, "The legal regulations of Diya (Blood-money) and the (ransom for) releasing of the captives, and the judgment that no Muslim should be killed in Qisas (equality in punishment) for killing a Kafir (disbeliever).
Reference: Sahih al-Bukhari 6915
In-book reference: Book 87, Hadith 53
USC-MSA web (English) reference(deprecated numbering scheme): Vol. 9, Book 83, Hadith 50