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Question: What is official or core Mormon doctrine?
Question: What is official or core Mormon doctrine?
Joseph Smith stated that the fundamental doctrine was "concerning Jesus Christ, that He died, was buried, and rose again the third day, and ascended into heaven"
Some people are fond of imposing their absolutist assumptions on the Church. Many hold inerrantist beliefs about scriptures or prophets, and assume that the Mormons have similar views. They therefore insist—without reason—that any statement by any Latter-day Saint Church leader represents Mormon doctrine and is thus something that is secretly believed, or that should be believed, by Mormons.
Joseph Smith defined our fundamental core doctrine:
The fundamental principles of our religion are the testimony of the Apostles and Prophets, concerning Jesus Christ, that He died, was buried, and rose again the third day, and ascended into heaven; and all other things which pertain to our religion are only appendages to it.
—Teachings of the Prophet Joseph Smith, p. 121.
Otherwise, Joseph Smith left clear revelation that the scriptures should govern the Church (D&C 42: 56-60), after having been submitted to and approved by all members of the First Presidency and Quorum of the Twelve (D&C 107:27), and submitted to the general body of the Church for ratification (D&C 26:2; 28:13).
What have other Church leaders said on the subject?
President George Q. Cannon (counselor in the First Presidency) explained that the scriptures are the only source of official doctrine, coupled with later revelation to the prophets that has been presented to the Church and sustained:
I hold in my hand the Book of Doctrine and Covenants, and also the book, The Pearl of Great Price, which books contain revelations of God. In Kirtland, the Doctrine and Covenants in its original form, as first printed, was submitted to the officers of the Church and the members of the Church to vote upon. As there have been additions made to it by the publishing of revelations which were not contained in the original edition, it has been deemed wise to submit these books with their contents to the conference, to see whether the conference will vote to accept the books and their contents as from God, and binding upon us as a people and as a Church. 
B.H. Roberts further explained that only those things within the Standard Works and those presented for a sustaining vote by the First Presidency and Council of the Twelve Apostles is binding upon the Church and its members:
The Church has confined the sources of doctrine by which it is willing to be bound before the world to the things that God has revealed, and which the Church has officially accepted, and those alone. These would include the Bible, the Book of Mormon, the Doctrine and Covenants, the Pearl of Great Price; these have been repeatedly accepted and endorsed by the Church in general conference assembled, and are the only sources of absolute appeal for our doctrine. 
Anything else, including books written by general authorities or general conference addresses, is valuable and may be of use for explanation, elucidation, exhortation, prophecy, and instruction, but does not bear the weight of ‘scripture’ in the LDS canon. Harold B. Lee was equally explicit:
If anyone, regardless of his position in the Church, were to advance a doctrine that is not substantiated by the standard Church works, meaning the Bible, the Book of Mormon, the Doctrine and Covenants, and the Pearl of Great Price, you may know that his statement is merely his private opinion. The only one authorized to bring forth any new doctrine is the President of the Church, who, when he does, will declare it as revelation from God, and it will be so accepted by the Council of the Twelve and sustained by the body of the Church. And if any man speak a doctrine which contradicts what is in the standard Church works, you may know by that same token that it is false and you are not bound to accept it as truth. 
Elsewhere, President Lee taught the same principle:
It is not to be thought that every word spoken by the General Authorities is inspired, or that they are moved upon by the Holy Ghost in everything they speak and write. Now you keep that in mind. I don't care what his position is, if he writes something or speaks something that goes beyond anything that you can find in the standard works, unless that one be the prophet, seer, and revelator—please note that one exception—you may immediately say, "Well, that is his own idea!" And if he says something that contradicts what is found in the standard works (I think that is why we call them "standard"—it is the standard measure of all that men teach), you may know by that same token that it is false; regardless of the position of the man who says it. 
In Mormon Doctrine, Elder Bruce R. McConkie was equally clear:
The books, writings, explanations, expositions, views, and theories of even the wisest and greatest men, either in or out of the Church, do not rank with the standard works. Even the writings, teachings, and opinions of the prophets of God are acceptable only to the extent they are in harmony with what God has revealed and what is recorded in the standard works. 
In areas in which the standard works are not clear, only the President of the Church may establish doctrine definitively:
But there are many places where the scriptures are not too clear, and where different interpretations may be given to them; there are many doctrines, tenets as the Lord called them, that have not been officially defined and declared. It is in the consideration and discussion of these scriptures and doctrines that opportunities arise for differences of views as to meanings and extent. In view of the fundamental principle just announced as to the position of the President of the Church, other bearers of the Priesthood, those with the special spiritual endowment and those without it, should be cautious in their expressions about and interpretations of scriptures and doctrines. They must act and teach subject to the over-all power and authority of the President of the Church. It would be most unfortunate were this not always strictly observed by the bearers of this special spiritual endowment, other than the President. Sometimes in the past they have spoken "out of turn," so to speak. Furthermore, at times even those not members of the General Authorities are said to have been heard to declare their own views on various matters concerning which no official view or declaration has been made by the mouthpiece of the Lord, sometimes with an assured certainty that might deceive the uninformed and unwary. 
- George Q. Cannon, "Comments," Millennial Star 42 no. 46 (15 November 1880), 724. (10 October 1880, General Conference)
- Brigham H. Roberts, sermon of 10 July 1921, delivered in Salt Lake Tabernacle, printed in Deseret News (23 July 1921) sec. 4:7.
- Harold B. Lee, The First Area General Conference for Germany, Austria, Holland, Italy, Switzerland, France, Belgium, and Spain of the Church of Jesus Christ of Latter-day Saints, held in Munich Germany, August 24–26, 1973, with Reports and Discourses, 69.
- Harold B. Lee, "The Place of the Living Prophet, Seer, and Revelator," Address to Seminary and Institute of Religion Faculty, BYU, 8 July 1964.
- Bruce R. McConkie, Mormon Doctrine, 2nd edition, (Salt Lake City: Bookcraft, 1966), 111. GL direct link
- J. Reuben Clark, “When Are the Writings or Sermons of Church Leaders Entitled to the Claim of Scripture,” address given to seminary and institute teachers at BYU, 7 July 1954, published in Church News (31 July 1954): 9–10; reprinted in Dialogue 12 (Summer 1979), 68–80.