یا ایها الرسول بلغ ما انزل الیک من ربک و ان لم تفعل فما بلغت رسالته و الله بعصمک من الناس ان الله لا یهدی القوم الکافرین
المائده 5/67

“O, Prophet, Proclaim the (Message) which has been sent to thee from your Lord. If you do not, you would not have fulfilled and proclaimed His Mission. And God will defend you from men (who corrupt) for God guides not those who reject Faith.” (5:67)

The tone of this verse shows that the assignment is a heavy one which has been placed upon the Prophet’s shoulders. He was anxious about the mission which might possibly meet up with opposition from the people. Thus the verse tells the Prophet that God commands the endeavors to have Islam be better understood and give him security and that he will be protected.

This important issue clearly does not relate to monotheism and polytheism in the struggle with the enemies from among the Jews and hypocrites, etc. because at the time of the revealing of this verse, this issue had been completely solved.

And, also, the announcing of the normal precepts of Islam did not have these dangers. From the external interpretation of the verse, it can be seen that it was a command which was of the same weight as the Divine mission. That is, if endeavors were not made, the truth of the Divine mission would not have been expressed. Can this command, then, be anything other than the selection of the successor to the Prophet? In particular, since the verse was revealed at the end of life of the Holy Prophet and it relates to the issue of the caliphate, which is the continuation of the issue of prophethood and the Divine mission of the Holy Prophet.

In addition, there are many Traditions recorded from a large group of the Companions of the holy Prophet including Zayd ibn Arqam, Abu Sa’id Khudri, ibn ‘Abbas, Jabir Abdallah Ansari, Abu Hurayrah, Hudaifah and ibfl Ma’sud. Some of these Traditions have come to us through eleven ways and a large number of them are from the Sunni scholars, both - these who transmit the Traditions, historians as well as recorders which say that the above verse was about Ali, peace be upon him, and that it was revealed on the day of Ghadir. (For further information, see the books Ahqaq al-Haq, al-Qadir, al-Maria‘at and Dalail al-Sadaq).

We will discuss the events of Ghadir, with the Will of God, in the section on Traditions but here we will simply remind ourselves that this is a clear sign because the Prophet of Islam was duty-bound to announce on the return from his last hajj and at the end of his life that he had officially selected Ali, peace be upon him, as his successor and introduce him to the people.