It is narrated from Sayyiduna Abdullah bin Amr (may Allah be pleased with them both) that people will perform Hajj together and stand at Arafah together without any imam. While they are encamped at Mina, suddenly a condition like that of a dog's bite (an inflaming frenzy) will seize them, and the tribes will fall upon one another and fight each other until the Aqabah (the mountain pass) flows with blood. Then in alarm they will seek refuge with the best of them, and they will come to him while he is weeping with his face turned towards the Ka'bah; it is as if I can see his tears. They will say: Come, let us pledge allegiance to you. He will say: Woe to you! How many covenants you have broken, and how much blood you have shed! So allegiance will be taken from him reluctantly. So when you find him, pledge allegiance to him, for he is the Mahdi on the earth and the Mahdi in the heaven.