300px|thumbnail|right|Sidney Rigdon, deliverer of the "salt sermon"
The salt sermon was an oration delivered on 17 June 1838 by Sidney Rigdon, then First Counselor in the First Presidency of the Church of Jesus Christ of Latter Day Saints,<!--Please do not change to The Church of Jesus Christ of Latter-day Saints. This was the most commonly used rendering in 1838. See MOS:LDS--> and frequent spokesman for Joseph Smith, the founder of the Latter Day Saint movement, against church dissenters, including Book of Mormon witnesses Oliver Cowdery, David Whitmer, and John Whitmer, and other leaders including W. W. Phelps. The Salt Sermon is often confused with Rigdon's July 4th oration.
Background
The years before 1838 were difficult for the members and leaders of Church of Jesus Christ of Latter Day Saints. LDS Church Apostle Heber C. Kimball would later say that the bank's failure was so shattering that afterwards "there were not twenty persons on earth that would declare that Joseph Smith was a prophet of God." While no summary or text of Rigdon's sermon remains, eyewitnesses indicated that Rigdon took the subject of his text from the fifth chapter of the Gospel of Matthew.
According to Rigdon, the dissenters were like the "salt" spoken of by Jesus (part of the metaphors of salt and light in the Sermon on the Mount) and must be "trodden under foot".
Corrill stated that "although [Rigdon] did not give names in his sermon, yet it was plainly understood that he meant the dissenters or those who had denied the faith." Their stories helped stir up anti-Mormon feeling in northwestern Missouri and contributed to the outbreak of the 1838 Mormon War.