There are not many events in the history of the world that are more exciting than the great meeting to be held at Adam-Ondi-Ahman. One of the major purposes for this meeting is to prepare the righteous for the coming of Christ (Teachings of the Prophet Joseph Smith p. 157). President Joseph Fielding Smith referred to the business conducted there as the "most momentous matters concerning the destiny of the earth..." Way to Perfection p. 289.
President John Taylor said that the meeting will "adjust the affairs of the world." President Taylor also said that this meeting will be a part of the restoration of all things. He also point out that the kingdom will be both Church and state together. (see The Gospel Kingdom p. 102, 116-118)
Adam comes to set in order the righteous and those who have held keys. It is truly the setting up of the kingdom in preparation to the coming of Christ. Elder Orson Pratt stated the all would be in confusion at the coming of Christ without the meeting at Adam-Ondi-Ahman (Journal of Discourses vol. 18 p. 344).
Elder Orson Pratt at another time explained the organization at Adam-Ondi-Ahman,
He (Adam) comes, then, as a great judge, to assemble this innumerable host of which Daniel speaks. He comes in flaming fire. The glory and blessing and greatness of his personage it would be impossible even for a man as great as Daniel fully to describe. He comes as a man inspired from the eternal throne of Jehovah himself. He comes to set in order the councils of the Priesthood pertaining to all dispensations, to arrange the Priesthood and the councils of the Saints of all former dispensations in one grand family and household.
(Journal of Discourses, 26 vols., 17:, p.186)
One of the most sacred and critcal parts of the meeting will be when the Savior is sustained as King of Kings and Lord of Lords,
THE ANCIENT OF DAYS. Daniel speaks of Adam as the Ancient of Days. In this dispensation the Ancient of Days will sit in the valley of Adam-ondi-Ahman; and the judgment will be set; Christ will come; and the kingdom will be turned over to Christ; and he will be sustained in his calling as King of Kings and Lord of Lords. [emphasis added] (Joseph Fielding Smith, Doctrines of Salvation, 3 vols., edited by Bruce R. McConkie, 1:, p.106)
President Joseph Fielding Smith saw the process of giving an account of keys that had been held as a form of judgment,
COMING OF CHRIST AT ADAM-ONDI-AHMAN. Daniel speaks of the coming of Christ, and that day is near at hand. There will be a great gathering in the Valley of Adam-ondi-Ahman; there will be a great council held. The Ancient of Days, who is Adam, will sit. The judgment-not the final judgment-will be held, where the righteous who have held keys will make their reports and deliver up their keys and ministry. Christ will come, and Adam will make his report. At this council Christ will be received and acknowledged as the rightful ruler of the earth. Satan will be replaced. Following this event every government in the world, including the United States, will have to become part of the government of God. Then righteous rule will be established. The earth will be cleansed; the wicked will be destroyed; and the reign of peace will be ushered in.
(Joseph Fielding Smith, Doctrines of Salvation, 3 vols., edited by Bruce R. McConkie, 3:, p.13)
Elder Bruce R. McConkie points out that it will precede the other appearances of the Lord that are associated with his second coming. The meeting will include all those who were at the first meeting at Adam-Ondi-Ahman and all faithful saints of all the ages past. It will be the greatest congregation of faithful saints ever assembled on planet earth. Elder McConkie suggests that there will be numerous meetings held. There will be the sacrament meeting that is mentioned in D&C 27. Some meetings may be for instruction of leaders, others for edification of all, some for worship, and some to conduct business. (see Millennial Messiah pp. 575-588)
For another post on Adam-Ondi-Ahman see the April 1 post on In The Doghouse blog.