Nasb-and-the-Nawasib

the Khilāfah due to him being the heir of Rasūl Allah H and his nominee. 1
And if that was true for him then the Abbasids were his heir, to the exclusion of
all else. This exactly was the reasoning of the Alawids.
The most glaring evidence that both parties clung to the same argument is the
correspondence that took place between him and al-Nafs al-Zakiyyah. Hence
when al-Nafs al-Zakiyyah wrote to him saying that they were the children of
Fāṭimah in Islam and that their father was ʿAlī who was the nominee of Rasūl
Allah H and the rightful Imām, he further asked, “So how did you inherit
his right whereas his children are alive?”
Al-Manṣūr rejected his claim by making a similar one saying, “We are the actual
inheritors of the seal of Prophets Q not you.” Thereafter he retorted to the
boasting of the Alawids about Fāṭimah J by saying:
بنو بنته وإنها لقرابة قريبة ولكنها ل يجوز لها الميراث،‏ ول ترث الولية ول يجوز لها اإلمامة،‏ فكيف
تورث بها؟ وبأن الله لم يجعل النساء كالعمومة واآلباء ول كالعصبة والولياء لن الله جعل العم أبا.‏
The children of his daughter, surely a very close bond of kinship. But
inheritance was not admissible for her and she could, thus, not inherit
rulership. And Imāmah was not permissible for her, so how could it be
inherited from her? Also, Allah has not given the women equal status as
the uncles and fathers, nor as the male inheritors and guardians, because
Allah has deemed the uncle a father.
And he said the following in response to their claim that ʿAlī was nominee of
Rasūl Allah H:
ميراث النبي له ‏)يعني للعباس(‏ والخالفة في ولده،‏ فلم يبق شرف ول فضل في جاهلية ول إسالم في الدنيا
واآلخرة إل والعباس وارثه ومورثه.‏
The inheritance of Nabī H was for him [ʿAbbās] and the Khilāfah is
now in his children. Hence there remains no honour or merit in Islam
1 Al-Kāmil fī al-Tārīkh 5/63.
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