Jesus said "Beware of false prophets" (Matthew 7:15) and the Apostle John warned that "many false prophets are gone out into the world" (1 John 4:1). How do we identify a false prophet? A key test is to examine the prophecies he or she has made in the name of the Lord. If a single one of those prophecies fail to come to pass, the speaker is identified as a false prophet and we are not to pay any attention to them (Deuteronomy 18:20-22).

A common LDS response to Joseph Smith and Brigham Young's numerous false prophecies is to dodge the serious implications by quoting Joseph Smith's own statement, "a prophet is only a prophet when he is acting as such." However, a careful examination of the following statements shows that LDS leaders were claiming prophetic authority when issuing these statements.

• David Whitmer - Recounts Joseph's failed prophesy regarding selling the copyright to the Book of Mormon in Canada. When Joseph was confronted with the failed prophecy, Joseph got a revelation through his seer stone that said, "Some revelations are of God; some revelations are of man; and some revelations are of the devil." —Address to All Believers in Christ, p. 31 (1887)
   
• Joseph Fielding Smith - Restrictions on blacks not getting the priesthood will not happen till the "far distant future" and "on some other world." — Answers to Gospel Questions, vol. 2, p. 188 (1958) [Historical note: Ban on Blacks receiving Mormon priesthood was lifted in 1978 after intense social pressure from both within and without the Mormon church.]
   
• Joseph Smith - A city shall be built, New Jerusalem [State of Missouri], in which a temple shall be reared in this generation — Doctrine and Covenants 84:3-5 (September 22 & 23, 1832)
   
• Joseph Smith - City of Zion, Missouri shall "become glorious, very great and very terrible," and "Surely Zion is the city of our God, and surely Zion cannot fall, neither be moved out of her place ..." Doctrine and Covenants 97:18-20 (August 2, 1833)
   
• Joseph Smith - Mormons will return to Zion, the only place God has appointed for the saints. [Zion is Independence, MO. The Mormons were driven out of Missouri in 1838. Doctrine and Covenants 101:16-21 (December 16, 1833)
   
• Joseph Smith - Treasure, gold and silver, would be found in Salem, Massachusetts and would be theirs. Doctrine and Covenants 111:1-11 (August 6, 1836)
   
• Joseph Smith - "Verily thus saith the Lord ..." David Patten to go on a mission the following spring (1839). —Doctrine and Covenants 114:1-2 (April 17, 1838)  In fact, Patten died in battle, Oct. 25, 1838. — History of the Church, vol. 3, p. 171 (October 25, 1838)
   
• Joseph Smith - Far West is to be a holy city and the location of the Lord's House. [No temple was ever built there.] Doctrine and Covenants 115:7-12 (April 26, 1838)
   
• Joseph Smith - The name of Oliver Granger shall be had in sacred remembrance from generation to generation, forever and ever. Doctrine and Covenants 117:12-15 (July 8, 1838)
   
• Joseph Smith - Revelation regarding John C. Bennett who is to help Joseph Smith, "And for his love he shall be great" — Doctrine and Covenants 124:16-17 (January 19, 1841). Joseph did make Bennett Nauvoo's mayor, but unbeknownst to Joseph, Bennett had abandoned his wife and family in Indiana and was professing to be Nauvoo's most eligible bachelor (Joseph Smith the Mormon, p. 147-148). Joseph would later write of Bennett: "It is evident that his general character is that of an adulterer of the worst kind. ... More than twenty months [since the Fall of 1840] ago Bennett went to a lady in the city and began to teach her that promiscuous intercourse between the sexes was lawful and no harm in it, and requested the privilege of gratifying his passions; ... and in order to finish the controversy, said and affirmed that I both taught and acted in the same manner — History of the Church, vol. 5, p. 42.
   
• John Whitmer - Prophecy about the Lord's return by Lyman Wight. — History of the Church, vol. 1, p. 176 (June 1831)
   
• Joseph Smith - Prophecy by the authority of Jesus Christ of a soon to come time of bloodshed, pestilence, hail, famine and earthquake. — History of the Church, vol. 1, p. 315 (January 4, 1833)
   
• Joseph Smith - Joseph's father's prophecy that Joseph would continue in the Priest's office until Christ comes. —History of the Church, vol. 1, p. 323 (January 23, 1833)
   
• Joseph Smith - the churches [LDS congregations] should "be in readiness to move to Jackson county in two years from the eleventh of September next, which is the appointed time for the redemption of Zion. ... you will learn by this we have a great work to do, and but little time to do it in;" — History of the Church, vol. 2, p. 145 (August 16, 1834)
   
• Joseph Smith - Made known to him in vision and by the Spirit that the coming of the Lord was nigh, 56 years should wind up the scene. — History of the Church, vol. 2, p. 182 (February 14, 1835)
   
• Joseph Smith - "I prophesy in the name of the Lord god of Israel, unless the United States redress the wrongs committed ... in a few years the government will be utterly overthrown and wasted, and there will not be so much as a potsherd left" — History of the Church, vol. 5, p. 394 (May 18, 1843)
   
• Joseph Smith - "I prophesy in the name of the Lord God of Israel, anguish and wrath and tribulation and the withdrawing of the Spirit of God from the earth await this generation, until they are visited with utter desolation. ... I prophesy they never will have power to kill me till my work is accomplished, and I am ready to die." — History of the Church, vol. 6, p. 58 (October 15, 1843)
   
• Brigham Young - A person of Jewish blood will always apostatize from the LDS faith. — Journal of Discourses, vol. 2, p. 142 (December 12, 1854)
   
• Brigham Young - Cain and his posterity will remain cursed and not receive the priesthood until all other children of Adam have had this privilege. — Journal of Discourses, vol. 2, p. 143 (December 12, 1854)
   
• Brigham Young - Before 26 years go by LDS elders will be as much thought of as kings on their thrones. —Journal of Discourses, vol. 4, p. 40 (August 31, 1856)
   
• Heber C. Kimball - "Brigham Young will become President of the United States." — Journal of Discourses, vol. 5, p. 219 (September 6, 1856)
   
• Brigham Young - The mark of Cain is a flat nose and black skin. — Journal of Discourses, vol. 7, p. 290 (October 9, 1859)
   
• Brigham Young - The curse will remain on blacks so that they can never hold the Mormon priesthood until all other descendants of Adam have received the promises and enjoyed the blessings of the Priesthood. — Journal of Discourses, vol. 7, p. 291 (October 9, 1859)
   
• Brigham Young - The present struggle (Civil War) will not free the descendants of Ham who are slaves. — Journal of Discourses, vol. 10, p. 250 (October 6, 1863)
   
• George Q. Cannon - A temple shall be reared in the Center Stake of Zion in the generation in which the the revelation was given. — Journal of Discourses, vol. 10, p. 344 (October 23, 1864), cf. D&C 84 prediction of temple to be built in Zion, Missouri.
   
• Brigham Young, "the only men who become Gods, even the Sons of God, are those who enter into polygamy." —Journal of Discourses, vol. 11, p. 269 (August 19, 1866)
   
• Orson Pratt - The Lord will return the Mormons to Zion in Jackson county Missouri. — Journal of Discourses, vol. 13, p. 138 (April 10, 1870)
   
• Orson Pratt - "God promised in the year 1832 that we should, before the generation then living had passed away, return and build up the City of Zion in Jackson County." — Journal of Discourses, vol. 13, p. 362 (May 5, 1870)
   
• Orson Pratt - "God said in the year 1832 ..." — Journal of Discourses, vol. 17, p. 111 (June 14, 1874)
   
• Brigham Young - For Congress to demand relinquishment of polygamy is to ask for renunciation of entire faith. All talk of another revelation is childish babble. Mormonism is in its entirety revelation from God or nothing at all. Millennial Star, vol. 27, p. 675-676
   
• Heber C. Kimball - Plurality of wives is a law established by God forever. It would be easier for the United States to build a tower to remove the sun as to remove polygamy. Millennial Star, vol. 28, p. 190
   
• Brigham Young - "as the Lord lives we will build up Jackson County in this generation" — Times & Seasons, vol. 6, p. 956 (April 6, 1845)