The completion of Islam on the day of Ghadir

History tells us that the enemies of the Prophet tried in many ways to thwart his divine mission- from accusing him of being mad, to being possessed by a demon, to attempting to kill him in his bed. But God's protective grace ensured that these evil schemes of the idolators came to naught. The last hope for these enemies was that with the death of the Prophet, the religion he brought would come to an end also:

Or do they say [of you], "A poet for whom we await a misfortune of time?" ( Sura al¬Tur, 52:30)

This was the thought that dominated many of the idolators and hypocrites. However, with the designation of such a worthy successor (Imam Ali), who had proven throughout his life so pure in faith and constant in devotion to Islam, the hopes of the enemies were transformed into despair. By this act, the continuity of the religious community was secured, its foundations set firm, and the blessing of Islam, with the designation of such leadership, was brought to completion. It is for this reason that, after the appointment of 'Ali as successor to the Prophet, the verse relating to the 'perfecting of religion' was revealed on the day of Ghadir:

This day are those who disbelieve in despair of [ever harming] your religion; so fear them not, fear Me. This day have I perfected your religion for you and completed My favour unto you, and have chosen for you Islam as religion.[1] (Sura al-Ma'ida, 5:3)[2]

With the designation of such a worthy successor (Imam Ali), who had proven throughout his life so pure in faith and constant in devotion to Islam, the hopes of the enemies were transformed into despair. By this act, the continuity of the religious community was secured, its foundations set firm, and the blessing of Islam, with the designation of such leadership, was brought to completion. 

...Determind by God or people?

Apart from the authentic hadiths -which go to prove that the issue of succession to the Prophet was a matter to be determined by God, rather than being left to the will of the community-various historical accounts also indicate that the Prophet, even when he was still in Mecca, not having yet established the Medinan state, regarded the issue of succession as one which pertained to God's decree. For instance, the chief of the tribe of Banu 'Amir came to the Prophet at the season of Hajj and asked him: 'If we pay allegiance to you, and you conquer your enemies, will we benefit from any share in the leadership [ of your community]?' In reply, the Prophet said:

'That is for God to decide; He will entrust leadership to whomever He will. '[3]

The chief of the tribe of Banu 'Amir came to the Prophet at the season of Hajj and asked him: 'If we pay allegiance to you, and you conquer your enemies, will we benefit from any share in the leadership [ of your community]?' In reply, the Prophet said:
'That is for God to decide; He will entrust leadership to whomever He will. '[3]

It is evident that if the issue of leadership were to be determined by the choice of the people, the Prophet would have had to say: 'This question pertains to the umma,' or that 'It is up to the 'folk who loose and bind"[4] to decide'; but the words of the Prophet in this connection are akin to those of God as regards the Message of Islam itself:

... God knoweth best with whom to place His Message. (Sura al-An'am,6: 124)

1. A group among the companions and the following generation understood this verse to relate to the event of Ghadir, amongst them being: Abu Sa'id al-Khudri, Zayd b. Arqam.jabir b. 'Abd Allah .al-Ansari, Abu Hurayra and Mujahid al-Makki. For the narrations of these indi¬viduals regarding the event in question, see 'Abd al-Husayn al-Amini, al-Ghad'ir (Beirut, 1387 /1967), vol. 1, pp. 230-3, which gives relevant citations from Kitab al-wilaya of Abuja'far al-Tabari, Kitab al-manaqib of Khatib Khwarazmi, Ma nuzila min al-quran fi 'Ali of Hafiz Abu Nu'aym Isfahani, and al-Wilaya of Abu Sa'id al-Sijistani; see also Khatib al¬Baghdadi, Ta'rikh Baghdad (Beirut, n.d.); and al-Suyuti, al-Durr al-manthur, vol. 2, p. 295, (for the narrations of lbn 'Asakir al-Shafi'I) ..
2. Fakhr al-Din al-Razi says in his al-Tafsir al-kabir (Beirut, n.d.), vol. 3,p. 369, that after the descent of this verse, the Holy Prophet lived for not more than 81 or 82 days, and the verse was not subject to abrogation or any other kind of amendment. Therefore, this verse must have been revealed on the day of Ghadir, which would have been the 8th of Dhi'l¬ Hijja, in the year of the Farewell Pilgrimage. Considering that, according to the Sunnis, the Prophet passed away on the 12sth of Rabi' al-Awwal, this would accord with the figure of 82 days precisely.
3.lbn Hisham, Sira, vol. 2, p. 422.
4. This term ahl al-hall wa 'l-' aqd denotes those deemed to have some degree of authority in the community.