It is narrated from Tharwan bin Milhan, he says: We were sitting in the mosque when Sayyiduna Ammar bin Yasir (may Allah be pleased with him) passed by us. We said to him: If you have heard anything from the Messenger of Allah (peace and blessings be upon him) about tribulation (fitnah), then please tell us. He said: I heard the Messenger of Allah (peace and blessings be upon him) say that after me, some people will come who will gain power by killing one another. We said to him: If any other person had narrated this hadith to us, we would not have believed him. He said: This will happen soon.