It is reported that Amir al-Mu’minin wrote in his letter to Sahl b. Hanif :

By Allah, I did not wrench the gate of Khaybar and throw it forty armlengths behind my back by the power of my body nor by a regimen. Rather, I was assisted by an angelic power and a soul illuminated by its Lord. I am of Ahmad just as light is of light. By Allah, had the Arabs unified upon my killing, I would not flee, and had I been given a chance to strike their necks, none would remain. He who is awaited by Gardens does not mind death. This was narrated to me along with its entire letter by Ahmad b. Musa al-Daqqaq . He said: Muhammad b. Harun al-Sufi narrated to us from Abi Bakr `Ubaydullah b. Musa al-Hibal al-Tabari. He said: Muhammad b. al-Husayn al-Khashab narrated to us. He said: Muhammad b. Muhsan narrated to us from Yunus b. Thibyan from al-Sadiq Ja`far b. Muhammad from his father from his forefathers .