False teachers appear in Nephite scripture as a cause of religious corruption. Nephi names them alongside pride and false doctrine in describing how churches become corrupted: “Because of pride, and because of false teachers, and false doctrine, their churches have become corrupted, and their churches are lifted up; because of pride they are puffed up” (2 Nephi 28:12). Those who preach false doctrine are condemned with the proud, the learned, and those who pervert the way of the Lord (2 Nephi 28:15).
During his ministry to the Nephites, Christ warned against false prophets, repeating the words he had given in the Sermon on the Mount: “Beware of false prophets, who come to you in sheep’s clothing, but inwardly they are ravening wolves” (3 Nephi 14:15; Matthew 7:15). He immediately provided the criterion for discerning them: “Ye shall know them by their fruits,” teaching that a corrupt tree cannot bring forth good fruit and that every tree not bearing good fruit is hewn down (3 Nephi 14:16-20).
The Book of Mormon presents several named individuals as fully developed examples of false teaching. Sherem denied Christ and challenged Jacob directly, using flattery and the power of speech to lead away many hearts (Jacob 7:2-7). Nehor preached that all mankind would be saved, that priests should not labor but be supported by the people, and he founded a counter-church after the manner of his preaching (Alma 1:3-6). Korihor declared there could be no Christ or atonement, taught that every man prospered according to his own genius and that there was no crime, and led away many converts to wickedness (Alma 30:12-18).
False prophets contributed to the decline of the Nephites after Christ’s visit. In the third century the people hardened their hearts and were led by many priests and false prophets to build up churches, commit iniquity, and attack the people of Jesus, dwindling in unbelief and wickedness until 230 years had passed (4 Nephi 1:34).