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 Banu Abbas reign until the people despair of goodness, then their affairs become diversified. If you find nothing but a scorpion’s hole, enter it, for there will be a long-lasting evil among the people, then their rule will disappear and the Mahdi will arise.

If the fifth of my family dies, there will be chaos, the seventh will die, and then so on until the Mahdi arises. He is Ibn Al-Afar, meaning Aaron.