Sultan Timur said, “Then what is it that has brought the caliphate to the Abbasids until this era in Islam?” He said this directly to me, and I replied: “May God grant you victory! Since the moment of the death of the Prophet, the Muslims have differed over whether or not it is necessary for the believers to have some ruler from among themselves to direct their spiritual and their worldly affairs. One party were of the opinion—and among them were the Kharijites—that it is not necessary; the majority, however, held that it is necessary, but have disagreed regarding the legal evidence proving its necessity. On the other hand, all the Shi‘ites adhered to the position that the Prophet designated ‘Ali [ibn Abī Tālib] to be caliph, although the Shi‘ites have more opinions than can be counted concerning the particular succession of ‘Ali’s descendants after him. The Sunnis, meanwhile, unanimously rejected the idea that the Prophet designated a successor. They assert that the only necessity with regard to this [the imamate] is ijtihād, by which they mean that it is incumbent upon the Muslims (as a community) to exert themselves in choosing a righteous, knowledgeable, and just man to whom to entrust the guidance of their affairs.

Abū Isḥāq Muḥammad ibn al-Wāthiq (Arabic: أبو إسحاق محمد بن هارون الواثق‎; c. 833 – 21 June 870), better known by his regnal name al-Muhtadī bi-'llāh (Arabic: المهتدي بالله, "Guided by God"), was the Caliph of the Abbasid Caliphate from July 869 to June 870, during the "Anarchy at Samarra".