It is narrated from Sayyiduna Abu Jabir al-Sadafi (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "After me there will be caliphs, after the caliphs there will be governors, after the governors there will be kings, and after the kings there will be tyrants. Then a man from my household will come forth who will fill the earth with justice just as it had been filled with oppression. Then the Qahtani will be made ruler; by the One who sent me with the truth, he will not be inferior to him."
Hadith Referenceالمعجم الكبير للطبراني / مسند من يعرف بالكنى / 19140