کتاب الفتن · نُعیم بن حماد

They will be destroyed if they disagree among themselves. The first sign of the cessation of their rule is a disagreement between them. The people will continue to be well in prosperity as long as the rule of the Abbasids is not ended. If their rule is ended, they will continue to be in turmoil until the Mahdi arises.

The last sign of the demise of the rule of the Banu Abbas are three kings among them who succeed one another. Their names are the names of the prophets. They will not exceed them after these kings. The duration of the Banu Abbas among these three kings is forty years. If you see differences among them, and a group of Banu Hashim gathered between the two rivers, and the mandate of a man from the Banu Abbas towards the west, and the clashing of the black flags, and zeroing in the navel of the Levant, and the killing of the governor of Egypt, and the prevention of its tax, then it is a sign of the interruption of their period.

The Mahdi will descend in Bayt al-Maqdis, then there will be caliphs from his family after him, their term will be prolonged, and they will be arrogant until the people pray against the Banu Abbas and the Banu Umayyad from what they receive from them.