Musannaf Ibn Abi Shayba 37:148

Yahya ibn Isa narrated to us, from al-A’mash, from Shahr, from a man who said: I was a leader (arif) during the time of Ali. He said: He commanded us with a command, then he said: "Have you done what I commanded you?" We said: "No." He said: "By Allah, you will surely do what you are commanded to do, or the Jews and the Christians will surely ride upon your necks."