The official text of the 1890 Manifesto reads:
To Whom It May Concern:
Press dispatches having been sent for political purposes, from Salt Lake City, which have been widely published, to the effect that the Utah Commission, in their recent report to the Secretary of the Interior, allege that plural marriages are still being solemnized and that forty or more such marriages have been contracted in Utah since last June or during the past year, also that in public discourses the leaders of the Church have taught, encouraged and urged the continuance of the practice of polygamy—
I, therefore, as President of the Church of Jesus Christ of Latter-day Saints, do hereby, in the most solemn manner, declare that these charges are false. We are not teaching polygamy or plural marriage, nor permitting any person to enter into its practice, and I deny that either forty or any other number of plural marriages have during that period been solemnized in our Temples or in any other place in the Territory.
One case has been reported, in which the parties allege that the marriage was performed in the Endowment House, in Salt Lake City, in the Spring of 1889, but I have not been able to learn who performed the ceremony; whatever was done in this matter was without my knowledge. In consequence of this alleged occurrence the Endowment House was, by my instructions, taken down without delay.
Inasmuch as laws have been enacted by Congress forbidding plural marriages, which laws have been pronounced constitutional by the court of last resort, I hereby declare my intention to submit to those laws, and to use my influence with the members of the Church over which I preside to have them do likewise.
There is nothing in my teachings to the Church or in those of my associates, during the time specified, which can be reasonably construed to inculcate or encourage polygamy; and when any Elder of the Church has used language which appeared to convey any such teaching, he has been promptly reproved. And I now publicly declare that my advice to the Latter-day Saints is to refrain from contracting any marriage forbidden by the law of the land.
President of the Church of Jesus Christ of Latter-day Saints.
President Lorenzo Snow offered the following:
"I move that, recognizing Wilford Woodruff as the President of the Church of Jesus Christ of Latter-day Saints, and the only man on the earth at the present time who holds the keys of the sealing ordinances, we consider him fully authorized by virtue of his position to issue the Manifesto which has been read in our hearing, and which is dated September 24th, 1890, and that as a Church in General Conference assembled, we accept his declaration concerning plural marriages as authoritative and binding."
The vote to sustain the foregoing motion was unanimous.
Salt Lake City, Utah, October 6, 1890.
The fact that this "revelation" came as Utah, whose population was mainly Mormon, was being denied statehood by the United States of America because of the practice of polygamy, was, of course, just a fantastic (and convenient) coincidence.
Interestingly, this "revelation" flatly contradicts a revelation given through Mormon founder and "prophet" Joseph Smith on July 12, 1843, which comprises Section 132 of Doctrine and Covenants and is still part of Mormon scripture today. Paragraphs 58-66 of Section 132 state:
58 Now, as touching the law of the priesthood, there are many things pertaining thereunto.
59 Verily, if a man be called of my Father, as was Aaron, by mine own voice, and by the voice of him that sent me, and I have endowed him with the keys of the power of this priesthood, if he do anything in my name, and according to my law and by my word, he will not commit sin, and I will justify him.
60 Let no one, therefore, set on my servant Joseph; for I will justify him; for he shall do the sacrifice which I require at his hands for his transgressions, saith the Lord your God.
61 And again, as pertaining to the law of the priesthood—if any man espouse a virgin, and desire to espouse another, and the first give her consent, and if he espouse the second, and they are virgins, and have vowed to no other man, then is he justified; he cannot commit adultery for they are given unto him; for he cannot commit adultery with that that belongeth unto him and to no one else.
62 And if he have ten virgins given unto him by this law, he cannot commit adultery, for they belong to him, and they are given unto him; therefore is he justified.
63 But if one or either of the ten virgins, after she is espoused, shall be with another man, she has committed adultery, and shall be destroyed; for they are given unto him to multiply and replenish the earth, according to my commandment, and to fulfil the promise which was given by my Father before the foundation of the world, and for their exaltation in the eternal worlds, that they may bear the souls of men; for herein is the work of my Father continued, that he may be glorified.
64 And again, verily, verily, I say unto you, if any man have a wife, who holds the keys of this power, and he teaches unto her the law of my priesthood, as pertaining to these things, then shall she believe and administer unto him, or she shall be destroyed, saith the Lord your God; for I will destroy her; for I will magnify my name upon all those who receive and abide in my law.
65 Therefore, it shall be lawful in me, if she receive not this law, for him to receive all things whatsoever I, the Lord his God, will give unto him, because she did not believe and administer unto him according to my word; and she then becomes the transgressor; and he is exempt from the law of Sarah, who administered unto Abraham according to the law when I commanded Abraham to take Hagar to wife.
66 And now, as pertaining to this law, verily, verily, I say unto you, I will reveal more unto you, hereafter; therefore, let this suffice for the present. Behold, I am Alpha and Omega. Amen.
The fact that this "revelation" came to Joseph Smith shortly after he’d been discovered to be having affairs with the wives of his followers was also a fantastic (and convenient) coincidence.
September 26, 2010 update: The commenter named Alma says that it's misinformation to say that President Woodruff claimed to have received a revelation. I offer the following, which is from an LDS church source:
EXCERPTS FROM THREE ADDRESSES BY
PRESIDENT WILFORD WOODRUFF
REGARDING THE MANIFESTO
The Lord will never permit me or any other man who stands as President of this Church to lead you astray. It is not in the programme. It is not in the mind of God. If I were to attempt that, the Lord would remove me out of my place, and so He will any other man who attempts to lead the children of men astray from the oracles of God and from their duty. (Sixty-first Semiannual General Conference of the Church, Monday, October 6, 1890, Salt Lake City, Utah. Reported in Deseret Evening News, October 11, 1890, p. 2.)
It matters not who lives or who dies, or who is called to lead this Church, they have got to lead it by the inspiration of Almighty God. If they do not do it that way, they cannot do it at all. . . .
I have had some revelations of late, and very important ones to me, and I will tell you what the Lord has said to me. Let me bring your minds to what is termed the manifesto. . . .
The Lord has told me to ask the Latter-day Saints a question, and He also told me that if they would listen to what I said to them and answer the question put to them, by the Spirit and power of God, they would all answer alike, and they would all believe alike with regard to this matter.
The question is this: Which is the wisest course for the Latter-day Saints to pursue—to continue to attempt to practice plural marriage, with the laws of the nation against it and the opposition of sixty millions of people, and at the cost of the confiscation and loss of all the Temples, and the stopping of all the ordinances therein, both for the living and the dead, and the imprisonment of the First Presidency and Twelve and the heads of families in the Church, and the confiscation of personal property of the people (all of which of themselves would stop the practice); or, after doing and suffering what we have through our adherence to this principle to cease the practice and submit to the law, and through doing so leave the Prophets, Apostles and fathers at home, so that they can instruct the people and attend to the duties of the Church, and also leave the Temples in the hands of the Saints, so that they can attend to the ordinances of the Gospel, both for the living and the dead?
The Lord showed me by vision and revelation exactly what would take place if we did not stop this practice. If we had not stopped it, you would have had no use for . . . any of the men in this temple at Logan; for all ordinances would be stopped throughout the land of Zion. Confusion would reign throughout Israel, and many men would be made prisoners. This trouble would have come upon the whole Church, and we should have been compelled to stop the practice. Now, the question is, whether it should be stopped in this manner, or in the way the Lord has manifested to us, and leave our Prophets and Apostles and fathers free men, and the temples in the hands of the people, so that the dead may be redeemed. A large number has already been delivered from the prison house in the spirit world by this people, and shall the work go on or stop? This is the question I lay before the Latter-day Saints. You have to judge for yourselves. I want you to answer it for yourselves. I shall not answer it; but I say to you that that is exactly the condition we as a people would have been in had we not taken the course we have.
. . . I saw exactly what would come to pass if there was not something done. I have had this spirit upon me for a long time. But I want to say this: I should have let all the temples go out of our hands; I should have gone to prison myself, and let every other man go there, had not the God of heaven commanded me to do what I did do; and when the hour came that I was commanded to do that, it was all clear to me. I went before the Lord, and I wrote what the Lord told me to write. . . .
I leave this with you, for you to contemplate and consider. The Lord is at work with us. (Cache Stake Conference, Logan, Utah, Sunday, November 1, 1891. Reported in Deseret Weekly, November 14, 1891.)
Now I will tell you what was manifested to me and what the Son of God performed in this thing. . . . All these things would have come to pass, as God Almighty lives, had not that Manifesto been given. Therefore, the Son of God felt disposed to have that thing presented to the Church and to the world for purposes in his own mind. The Lord had decreed the establishment of Zion. He had decreed the finishing of this temple. He had decreed that the salvation of the living and the dead should be given in these valleys of the mountains. And Almighty God decreed that the Devil should not thwart it. If you can understand that, that is a key to it. (From a discourse at the sixth session of the dedication of the Salt Lake Temple, April 1893. Typescript of Dedicatory Services, Archives, Church Historical Department, Salt Lake City, Utah.)
Those who find it curious that a Mormon President should contradict the pronouncements of a previous Mormon President should keep in mind that the President of the Church of Jesus Christ of Latter-day Saints is a "Prophet, Seer and Revelator." Whoever happens to be the current President is considered to be a "living prophet," and his pronouncements take precedents over those of his predecessors, even if they contradict the pronouncements of previous church Presidents.
There was indeed another statement on the subject--commonly known as the Second Manifesto--presented by President Joseph F. Smith, Sr. at the Third Day-Afternoon Session of the Seventy-Fourth Annual Conference of the Church of Jesus Christ of Latter-day Saints on April 6, 1904. It reads:
Now I am going to present a matter to you that is unusual and I do it because of a conviction which I feel that it is a proper thing for me to do. I have taken the liberty of having written down what I wish to present, in order that I may say to you the exact words which I would like to have conveyed to your ears, that I may not be misunderstood or misquoted. I present this to the conference for your action: OFFICIAL STATEMENT
"Inasmuch as there are numerous reports in circulation that plural marriages have been entered into contrary to the official declaration of President Woodruff, of September 26, 1890, commonly called the Manifesto, which was issued by President Woodruff and adopted by the Church at its general conference, October 6, 1890, which forbade any marriages violative of the law of the land; I, Joseph F Smith, President of the Church of Jesus Christ of Latter-day Saints, hereby affirm and declare that no such marriages have been solemnized with the sanction, consent or knowledge of the Church of Jesus Christ of Latter-day Saints, and "I hereby announce that all such marriages are prohibited, and if any officer or member of the Church shall assume to solemnize or enter into any such marriage he will be deemed in transgression against the Church and will be liable to be dealt with, according to the rules and regulations thereof, and excommunicated therefrom.
"JOSEPH F. SMITH, "
President of the Church of Jesus Christ of Latter-day Saints.
They charge us with being dishonest and untrue to our word. They charge the Church with having violated a "compact," and all this sort of nonsense. I want to see today whether the Latter-day Saints representing the Church in this solemn assembly will not seal these charges as false by their vote.
President Francis M. Lyman presented the following resolution and moved its adoption: RESOLUTION OF ENDORSEMENT
"Resolved that we, the members of the Church of Jesus Christ of Latter-day Saints, in General Conference assembled, hereby approve and endorse the statement and declaration of President Joseph F Smith just made to this Conference concerning plural marriages, and will support the courts of the Church in the enforcement thereof."
The resolution was seconded by a number of Presidents of Stakes and prominent Elders. Elder B. H. Roberts, in seconding the resolution, spoke as follows:
"In seconding the resolution that has just been read-which I most heartily do-I desire to state at least one reason for doing it. As remarked by the president, the Church of Jesus Christ of Latter-day Saints has been accused of being covenant-breakers with this nation. Of course, there never was, and could not be, any compact between the Church and the general government of the United States. But there could be a compact between the State of Utah and the United States, and there was such a compact made in the Constitution of our state, by and through the Constitutional Convention. And now I am pleased with the opportunity of the Church saying in its official capacity that the Latter-day Saints not only now are, but have been, true to the compact between the State of Utah and the United States, and that they are true to the Constitution of the state, which, by express provision, forever prohibited plural or polygamous marriages, and made that irrevocable, without the consent of the United States. The adoption by the Church of this resolution should put to silence those who have accused us of being covenant-breakers."
The resolution was then adopted, by unanimous vote of the Conference.
The fact that the Second Manifesto was issued brings up the question of why such a statement would be necessary if the 1890 Manifesto had been telling the truth.