Musnad Ahmad 5:809

'Abdullah narrated to us, Isma'il Abu Ma'mar narrated to me, 'Abdullah ibn Idris narrated to us, 'Asim ibn Kulayb narrated to us, from his father, who said: I was sitting with 'Ali, may Allah be pleased with him, when a man wearing travel clothes entered upon him. He sought permission from 'Ali, may Allah be pleased with him, while he was speaking to the people, so he was occupied away from him. Then 'Ali, may Allah be pleased with him, said: I entered upon the Messenger of Allah, may Allah be pleased with him and grant him peace, and 'Aishah, may Allah be pleased with her, was with him. He said to me: "How will you be with a people such and such?" I said: "Allah and His Messenger know best." Then he repeated it, and I said: "Allah and His Messenger know best." He said: Then he said: "A people who will emerge from the direction of the east, reciting the Qur'an, it does not pass beyond their collarbones. They will pass through the religion just as an arrow passes through the game. Among them is a man with a deformed hand, as if his hand is the breast of an Abyssinian woman." I adjure you by Allah, did I inform you that they are among them? Then he mentioned the hadith in its entirety.