Musannaf Ibn Abi Shaybah

Hazrat Suwaid bin Harith narrates from Hazrat Ali (may Allah be pleased with him) that he said: There will be a decline in (the practice of) Islam until Allah, Allah is no longer said. When this happens, the leaders of the religion will strike with their tails (meaning that people will follow their leaders in tribulation). When this happens, some people will rise who will gather like clouds in autumn, and by Allah, I know the name of their leader and even the places where their mounts will be made to sit.