Abu Ya'la (d. 458 AH) a leading Hanbali scholar along with Ibn Taymiyyah, resembled Mawardi(d. 450AH) in his thought about the Khilafah. Abu Ya'la quotes Imam Ahmad ibn Hanbal that the Muslims would be in a state of Fitnah if there was no Khaleef. Page 125, Mahmood A. Ghazi's Book 'Political and Constitutional Thought of Islam' Qadi Abd al Jabbar (d. 415 AH,1025AD) He wrote extensively on the subject, some of his works include: Sharh al-Usul al Khamsah Al-Mughni fi Abwab al-Tawhid Wa'l Adl The establishment of the Khilafah according to the Qadi in compulsory upon the Ummah, because many of the obligations of Islam cannot be fulfilled without the Khilafah, stating the well known principle: Ma la Yatimmu'l Wajib Illa Bihi Fahuwa Wajib [Whatever the wajib cannot be accomplished without is itself a wajib] He also discusses the concept of Imamah in the context the Quranic principle of Amr bi'l Maruf wa'l Nahy An al-Munkar[Enjoining of the Good and the F
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