When the matter of Wilayah (guardianship) and governance is resolved for a nation—the way it happened on the day of Al-Ghadir—that day is indeed an Eid, a day of celebration, for that nation. For, the most important and crucial matter for every nation is the issue of governance, Wilayah, management, and the ruling of the society; hence, this event is the most determining matter of a nation. Every nation has resolved the issue [of establishing a guardianship and a governing body] in a way[...]
Wilayah, which represents governance and leadership in the Islamic society, is naturally different from governance in a non-Muslim community. In Islam, the leadership of the society belongs to God the Almighty. No person has the right to take on the management of other people's affairs. This right is specific to God—who is the Creator, the Origin; He knows what is expedient for the people, He is the Master of people's affairs, indeed He is the Master of the affairs of even the tiniest entities of existence.
The mere fact that such a way of thinking prevails in the Islamic society is an extraordinary phenomenon. No power, no cutting sword, no amount of wealth, no power of science and prudence entitles anyone to decide on the fates of other humans. These are values. No one is granted the right of leadership of the people. This is a right exclusively owned by God.
God, the Elevated, practices this leadership through specific mediums. That is, even when the governor or the ruler of the Muslims is given the authority to manage the affairs of the people, either by appointment--like what is the case for Imam Ali (a.s) and prophet Muhammad (p.b.u.h.) in our belief-- or through criteria and principles [of slection], this wilayah is still a wilayah of God. This right to rule is God's right. This is the power and ruling of God over the people. That person—be it anyone-- without divine power and wilayah, has no right over other people. This is an important and determining factor in the fate of the Islamic society.
The person who is given the responsibility of wilayah by God, must realize, show or own some degrees of the [features of] divine wilayah. The features of the divine wilayah include power, wisdom, justice, mercy, etc. The person or entity that takes on the role of ruling over the people, must be a manifestation of God's power, justice, mercy and wisdom. This characteristic distinguishes the Islamic society from all other societies that are governed with other methods. Ignorance, self-satisfying desires, personal taste based on one's own profits and interest have no right to influence the people's life and the management of their affairs. Thus, in the Islamic system and society, justice, knowledge, religion and mercy must rule. Self-centeredness or personal desires --of anyone or in anyone's words or behavior-- must not rule.
The secret to the purity of Imam, in the ultimate, original form of it in Islam, is that no possibility of making mistakes or errors exists. Even when purity is not there, religion, piety (taqwa) and justice must rule over the people, which is regarded as an example of divine wilayah.
Hence the day of Ghadir is the day of wilayah, a determinant and important day, in the fate of the Islamic society.