designation as the successor of Muhammad. For instance, the Shia al-Mufid () writes that this hadith invested in Ali all the privileges which Aaron had received from Moses except prophethood. In particular, Ali was the deputy of Muhammad just as Aaron was the deputy of Moses, which implies that Ali was the rightful successor to Muhammad. Sunni views Despite its Shia coloring, the Hadith of Position nevertheless remains prominent in Sunni sources as one of the most important pieces of evidence supporting the finality of Muhammad in the chain of prophets. In response to the Shia claims, Sunni scholars argue that the Hadith of Position is irrelevant to Muhammad's succession because Aaron died before Moses. The Shia Sharif al-Murtaza () counters that had Aaron survived Moses, the former would have surely succeeded the latter. The Shia al-Kulayni () adds that Moses' successor Joshua later designated the progeny of Aaron to succeed him instead of his own or Moses'. Al-Kulayni suggests that Joshua did so because it was the divine choice. Ghadir Khumm Shortly before his death in 632, Muhammad performed the Hajj rituals in Mecca. In his sermon in Mecca and again later at the Ghadir Khumm by some accounts, he alerted Muslims about his impending death. After the Hajj, Muhammad set off on the return journey from Mecca to Medina, accompanied by a large number of pilgrims. On the way, Muhammad called the Muslim caravan to a halt at the Ghadir Khumm before the pilgrims parted to go their separate ways. After the noon prayer, Muhammad delivered a sermon in which he famously said, "He whose I am, Ali is his ." Muhammad repeated this three or four more times, as reported in Musnad Ibn Hanbal, a canonical Sunni source. By some Shia and Sunni accounts, he then continued, "O God, befriend the friend of Ali and be the enemy of his enemy," which might have been the standard formula for pledging allegiance at the time, used later both by Ali and his son Hasan during their caliphates. As reported in Musnad Ibn Hanbal, Muhammad's companion Umar congratulated Ali after the sermon and told him, "You have now become of every faithful man and woman." Historicity The historicity of the Ghadir Khumm is rarely disputed within the Muslim community, as its recorded tradition is "among the most extensively acknowledged and substantiated" in classical Islamic sources, even as the statements