Musannaf Ibn Abi Shayba 38:171

Ubayd Allah told us, he said: Nu'aym ibn Hakim informed us, he said: Abu Maryam told me that Shabath ibn Rib'i and Ibn al-Kawwa' went out from Kufa to Harura'. Ali ordered the people to go out with their weapons, so they went out to the mosque until the mosque was filled. Ali sent [a message]: "How evil is what you have done by entering the mosque with your weapons! Go to the graveyard of Murad until my command comes to you." Abu Maryam said: We set off to the graveyard of Murad and we were there for an hour of the day. Then it reached us that the people had returned and were marching. I said: "I will go and look at them." I set off and began to weave through their ranks until I reached Shabath ibn Rib'i and Ibn al-Kawwa', and they were standing, leaning on their mounts, and Ali’s messengers were with them, adjuring them by Allah to return. They were saying to them: "We seek refuge for you with Allah from hastening a tribulation this year for fear of the coming year." A man among them stood up to one of Ali’s messengers and hamstrung his mount, so the man dismounted while saying "To Allah we belong and to Him we shall return," then he carried his saddle and left. They [Shabath and Ibn al-Kawwa'] were saying: "We sought nothing but to oppose them," while they [the messengers] were adjuring them by Allah. They remained for an hour, then they departed to Kufa as if it were the day of Adha or the day of Fitr. He [Ali] used to tell us before that that a people would emerge from Islam, passing through it as an arrow passes through the game, their sign being a man with a deformed hand. I heard that many times. Nafi' al-Mukhadda' also heard it until I saw him loathing his food from how much he heard it from him. Nafi' was with us in the mosque, praying in it by day and spending the night in it, and I had clothed him in a burnous. I met him the next day and asked him: "Did the people who went out to Harura' go out with us?" He said: "I went out intending them, until when I reached the tribe of so-and-so, some boys met me and took my weapons, so I returned." When a year or so had passed, the people of Nahrawan went out, and Ali marched toward them, but I did not go out with him. My brother Abu Abd Allah and his freedman went out with Ali. Abu Abd Allah informed me that Ali marched toward them until, when he was opposite them on the bank of the Nahrawan, he sent to them, adjuring them by Allah and ordering them to return. His messengers kept going back and forth to them until they killed his messenger. When he saw that, he rose against them and fought them until he had finished them all. Then he ordered his companions to search for the deformed one. They searched for him, and some of them said: "We do not find him alive," and some said: "He is not among them." Then a man came to him and gave him glad tidings, saying: "O Commander of the Faithful, by Allah, we have found him under two slain men, in his legs." He said: "Cut off his deformed hand and bring it to me." When it was brought to him, he took it in his hand, then raised it and said: "By Allah, I did not lie, nor was I lied to."