“He did it because of al-Manāfiyya—that is, because we all belong to Banū Abd Manāf.”
A court case once arose concerning which one of the chief justices consulted me. He brought me a book in which the case was recorded. They did not understand this expression—the word al-Manāfiyya—so I explained it to them and clarified its meaning.
The point is that the Banū Abd Manāf were initially united during the time of the Prophet—may Allah bless him and grant him peace—Abū Bakr, and Umar. Division arose among them only afterward, when they became divided over political leadership. Likewise, the Banū Hāshim remained united during the time of the four caliphs and throughout the Umayyad era. Division arose only when the Banū al-Abbās assumed power and division and disagreement developed between them and some of the Banū Abī Tālib(1).
This is how people ordinarily behave: a people remain united so long as there is no position, wealth, or anything else over which they might contend. If they have an opponent, they form one united coalition(2) against him; but once authority passes to them, they quarrel and become divided.
Thus, during the Umayyad caliphate, the Banū Hāshim—including the families of Alī, al-Abbās, and others—were united, with no dispute among them. When someone arose to advocate their cause, he called for “the chosen one from the House of Muhammad” without identifying him. The Alids hoped that rule would fall to them(3), whereas Jafar ibn Muhammad and others already knew that this authority would belong only to the Banū al-Abbās. When they overthrew(4) the Umayyad state, rule passed to the Hāshimites, and al-Saffāh built a city