Ghadir was a matter of establishing a criterion although the Holy Prophet's (PBUH) advice was not heeded later on.
Until the end of time, Muslims can use this criterion to determine the main path of the Islamic Ummah. Choosing the best time for
declaring his successor was not up to the Holy Prophet (s.w.a.). Rather, it was decided by Allah the Exalted.
"Deliver what has been revealed to you from your Lord." [The Holy Quran, 5: 67] This is not to say that the Prophet (s.w.a.)
did not know about the issue of Imamate and Wilayat before the revelation. He knew about this issue since the time he was
appointed a prophet. Moreover, the events that happened during his 23-year prophet hood left no doubt about Imamate and Wilayat.
But Wilayat had to be publicly declared at the most strategic time, and it was declared after a divine order. "Deliver what has
been revealed to you from your Lord. And if you do not do it, then you have not delivered His message." [The Holy Quran, 5: 67] That is
to say, declaring Wilayat was a divine message that the Prophet (s.w.a.) had to deliver. Later on, when the Holy Prophet (s.w.a.)
told the pilgrims to gather in Ghadir al-Khumm and declared this divine message, this ayah was revealed to him: "Today I have
perfected your religion for you, and I have completed My blessing upon you." [The Holy Quran, 5: 3]
Islam and divine blessings were complete on Ghadir.
"Today the unbelievers have despaired of your religion. Therefore, fear them not, but fear Me.
" [The Holy Quran, 5: 3] Allah told the Prophet (s.w.a.) that Ghadir was the day when his enemies despair.
That is to say, the criterion was determined. From that day on, Muslims could see the criterion and end doubts whenever
they opened their eyes to the realities. This shows the importance of Ghadir.