It is narrated from Sayyiduna Ali (may Allah be pleased with him), the Messenger of Allah (peace and blessings of Allah be upon him) said: "The Mahdi will be from us, that is, from the Ahl al-Bayt. Allah Almighty will set his affairs right in a single night."
Hadith Referenceسلسله احاديث صحيحه / الفتن و اشراط الساعة والبعث / 3635