Verse of ikmal al-din

Shortly before he died in 632 CE, the Islamic prophet Muhammad performed the Hajj ritual in Mecca, which has become known as his Farewell Pilgrimage.[2] In his sermon in Mecca at Arafat, and also later at the Ghadir Khumm by some accounts, he alerted Muslims about his impending death.[3][4][5] On his return trip to Medina after performing the Hajj, Muhammad called the Muslim caravan to a halt at the Ghadir Khumm (lit. 'pond of Khumm').[6]

There Muhammad gave a sermon in which he announced, "Anyone who has me as his mawla, has this Ali as his mawla,"[7][8][3] as reported by some canonical Sunni and Shia sources, including Musnad Ibn Hanbal and al-Ghadir.[9][10][4] In particular, the former source adds that Muhammad repeated this statement three or four times and that his companion Umar congratulated Ali after the sermon, "You have now become mawla of every faithful man and woman."[11][3][12]

While the authenticity of the Ghadir Khumm is rarely contested, the interpretation of the Arabic word mawla is a source of controversy between Sunni and Shia.[3][13] In this context, Shia sources interpret this word as meaning 'leader', 'master', or 'patron',[4][14] and thus see the Ghadir Khumm as the appointment of Ali to succeed Muhammad on both the spiritual and temporal levels,[4] while Sunni accounts of this sermon tend to offer little explanation or substitute the word wali (of God, lit. 'friend of God') in place of mawla.[3] Sunni authors argue that Muhammad did not explicitly refer to Ali as his successor in his sermon,[4] while the Shia writer Abdul Hosein Amini (d. 1970) enumerates the Sunni and Shia sources that corroborate the Shia interpretation in his multivolume al-Ghadir.[4][15]

Muhammad H. Tabatabai (d. 1981), author of the seminal Shia exegesis Tafsir al-mizan, argues in his work that 'today' in the verse of ikmal is the day of the Ghadir Khumm. In particular, the unbelievers' despair in the verse of ikmal followed Muhammad's designation of Ali to guide the nascent Muslim community, he writes.[24] The enemies of Islam despaired from destroying it,[25] suggests Tabatabai, because Ali's leadership would have rightly guided the Muslim community.[24]

Tabatabai contends that the perfection of religion in the verse of ikmal is the guardianship (walaya) of Ali, as opposed to the closure of Islamic legislation, advanced by some Sunni scholars. According to Tabatabai, this Sunni view ignores the injunctions about riba which were revealed after the verse of ikmal. The Islamicist Hamid Mavani adds that the traditions cited by Tabatabai are mutawatir, that is, they have numerous, uninterrupted chains of transmission.[21] Tabatabai elsewhere challenges the prevalent Sunni view by arguing that the perfection of Islam in this verse cannot refer to a minor occasion such as the promulgation of a religious injunction.[26] He also maitains that the perfection of religion in the verse of ikmal was the fulfillment of an earlier divine promise in verse 24:55, which reads,

God has made a promise to those among you who believe and do good deeds: He will make them successors to the land, as He did those who came before them; He will strengthen the religion He has chosen for them; He will grant them security to replace their fear. They worship Me and do not join anything with Me.[24]

For Tabatabai, the authority of the divine guides (ulu al-amr) completes the spiritual authority (walaya) of God and His prophet. Nevertheless, he adds, all this was conditional on the submission of Muslims to their divine instructions at the Ghadir Khumm per verse 8:53 of the Quran, which includes the passage, "God would never change a favor He had conferred on a people unless they changed what was within themselves."[24]