The Holy Bible, Daniel 7:9-10,13-14

9 I beheld till the thrones were cast down, and the Ancient of days did sit, whose garment was white as snow, and the hair of his head like the pure wool: his throne was like the fiery flame, and his wheels as burning fire.

10 A fiery stream issued and came forth from before him: thousand thousands ministered unto him, and ten thousand times ten thousand stood before him: the judgment was set, and the books were opened.

13 I saw in the night visions, and, behold, one like the Son of man came with the clouds of heaven, and came to the Ancient of days, and they brought him near before him.

14 And there was given him dominion, and glory, and a kingdom, that all people, nations, and languages, should serve him: his dominion is an everlasting dominion, which shall not pass away, and his kingdom that which shall not be destroyed.

The Doctrine and Covenants, Section 116:1

1 Spring Hill is named by the Lord Adam-ondi-Ahman, because, said he, it is the place where Adam shall come to visit his people, or the Ancient of Days shall sit, as spoken of by Daniel the prophet.

Doctrine and Covenants Student Manual, Section 116

Elder Joseph Fielding Smith said that the council at Adam-ondi-Ahman, as prophesied in Daniel 7:9-14, will be “of the greatest importance to this world. At that time there will be a transfer of authority from the usurper and impostor, Lucifer, to the rightful King, Jesus Christ. Judgment will be set and all who have held keys will make their reports and deliver their stewardships, as they shall be required. Adam will direct this judgment, and then he will make his report, as the one holding the keys for this earth, to his Superior Officer, Jesus Christ. Our Lord will then assume the reins of government; directions will be given to the Priesthood; and He, whose right it is to rule, will be installed officially by the voice of the Priesthood there assembled. This grand council of Priesthood will be composed, not only of those who are faithful who now dwell on this earth, but also of the prophets and apostles of old, who have had directing authority. Others may also be there, but if so they will be there by appointment, for this is to be an official council called to attend to the most momentous matters concerning the destiny of this earth. When this gathering is held, the world will not know of it; the members of the Church at large will not know of it, yet it shall be preparatory to the coming in the clouds of glory of our Savior Jesus Christ as the Prophet Joseph Smith has said. The world cannot know of it. The Saints cannot know of it—except those who officially shall be called into this council—for it shall precede the coming of Jesus Christ as a thief in the night, unbeknown to all the world.” (Way to Perfection, pp. 290-91.)

Conference Report, Ezra Taft Benson, October 1954

[O]ur first parents were placed in the Garden of Eden…here in America, [and]… it was here also where Adam met with a body of great high priests at Adam-ondi-Ahman shortly before his death and gave them his final blessing, and that to that same spot he is to return again to meet with the leaders of his people…

Conference Report, Orson F Whitney, April 1927

The world has not seen the last of Father Adam. He is coming again–coming as the Ancient of Days, to fulfill the prophecy of Daniel concerning him. And he will come to the very place where, bowed with the weight of his nine centuries (men kept the Word of Wisdom in those days), he blessed his posterity before the close of his earthly career. In the Valley of Adam-ondi-Ahman, now in Western Missouri, almost within hailing distance of the ancient site of the Garden of Eden, where the New Jerusalem is to rise, will sit the Ancient of Days, counseling his worthy children and preparing them for the second coming of the Son of God.

History of the Church, Joseph Smith 3:35

In the afternoon I went up the river about half a mile to Wight’s Ferry, … for the purpose of selecting and laying claim to a city plat near said ferry in Daviess County, … which the brethren called “Spring Hill,” but by the mouth of the Lord it was named Adam-ondi-Ahman, because, said He, it is the place where Adam shall come to visit his people, or the Ancient of Days shall sit, as spoken of by Daniel the Prophet.

History of the Church, Joseph Smith 3:386

Daniel in his seventh chapter speaks of the Ancient of Days; he means the oldest man, our Father Adam, Michael, he will call his children together and hold a council with them to prepare them for the coming of the Son of Man. He (Adam) is the father of the human family, and presides over the spirits of all men, and all that have had the keys must stand before him in this grand council. This may take place before some of us leave this stage of action. The Son of Man stands before him, and there is given him glory and dominion. Adam delivers up his stewardship to Christ, that which was delivered to him as holding the keys of the universe, but retains his standing as head of the human family.

Journal of Discourses, Orson Pratt 17:29

A hundred million people stood before this personage–the Ancient of days. …[or]… father Adam [and] … 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. What is all this for? … It is to prepare the way for another august personage whom Daniel saw coming with the clouds of heaven, namely the Son of Man… This explains the reason why our father Adam comes as the Ancient of days with all these numerous hosts, and organizes them according to the records of the book, every man in his place, preparatory to the coming of the Son of Man to receive the kingdom. Then every family that is in the order of the Priesthood, and every man and every woman, and every son or daughter whatever their kindred, descent or Priesthood, will know their place… This man, will sit upon his throne, and ten thousand times ten thousand immortal beings–his children–will stand before him, with all their different grades of Priesthood, according to the order which God has appointed and ordained. Then every quorum of the Priesthood in this Latter-day Saint Church will find its place, and never until then.

Journal of Discourses, Orson Pratt 18:42

And I have no doubt, if we had the Book of Enoch referred to in the revelation, in which book all the prophecies predicted by this aged man are written, we would find something predicted about his posterity now living. I think he would tell about his coming as the Ancient of Days, the great Prince, to his posterity. He told his children in that grand Conference all about it, and they understood it, and it was all written in the Book of Enoch, to be testified to in due time. These perhaps are some of the books that are to be opened on that grand occasion. You may ask, Why the necessity of this vast multitude from the heavens to assemble here on the earth? It is to fulfill many prophecies besides that of Daniel; it is to fulfill prophecies that have been predicted by all holy men that understood the great events of the latter days, that the Saints who are in heaven are to come down here on the earth, and are to be organized here on the earth, and are to be united with the Saints on the earth, as one grand company, each one understanding his place. I do not think there will be any contentions or jealousies, as for instance, whether the high Priests are greater than the Seventies, but all will understand their proper place and position, because their positions will be pointed out to them by the Ancient of Days, the father and prince of all, even down to those last ordained to the Priesthood. Perhaps these records will recall the positions we are all to occupy; for I believe, to the Lord was known the end from the beginning. But why all this? Why should it be given to all to know their proper places? Why should the books be opened, and why should the fourth beast be destroyed and the body given to the burning flame? It is explained in the same connection–”I saw in the night visions, and behold one like the Son of Man came with the clouds of heaven.” To whom does this glorious personage come? He comes to the Ancient of Days. What, that personage coming in glory, majesty and dominion, with the clouds of heaven, to the Ancient of Days! What for? In order that he might receive from him the kingdom, in its order, every person standing in his proper position, everything organized after the most perfect order. The Ancient of Days delivers up the kingdom, thus completed, to the Son of Man, whose dominion becomes so great that all peoples, nations and languages serve him; and his dominion is everlasting and shall have no end.

Journal of Discourses, Orson Pratt 18:42

Who would be the most likely person to fill this important position? He is called the Ancient of Days. Can you tell me, who the most ancient person is that lived on the earth, during the most ancient days? All, all will acknowledge that it is Adam. Inasmuch as he has proven himself a righteous man, it is right and proper that he should by divine appointment, have dominion over the righteous of his posterity, who should exist from his day, down to that period, when he comes in his glory; and this ten thousand times ten thousand spoken of will be the faithful of his own posterity. They shall stand before him, and certain books are then to be opened. If we understand the nature of those records, we should doubtless find much written concerning kingdoms, nations and individuals. They are the records which are kept in heaven, in which all things pertaining to the peoples of the earth are recorded. Or, as the Book of Mormon expresses it, giving the language of the Savior when on this American continent, that “all things are written by the Father;” that is, by his authority, by his direction are all things written. The records of the nations–their rise and decadence, with everything pertaining to them, in a national capacity, will be written. Then there will be the records of families and of individuals, even of all people and tongues of the earth. The books will be opened, and the judgment will sit. What judgment? Not the final judgment, because that is to take place more than a thousand years after this. This judgment refers to the nations that will then exist, and it is out of these records and by this judgment will they be judged. The calamities spoken of will take place in fulfillment of the Scriptures, and of the great purposes of Jehovah.