Joseph Smith–Matthew (abbreviated as JS-M) is a retranslation of portions of the Gospel of Matthew from verses 23:39 to 24:51 which Mormons believe was revealed to their prophet Joseph Smith.
Mormon belief is that JS-M stands in as a witness to the world of Joseph Smith’s mission as a prophet of God in the last days, and it was published in 1831. It is clear that Smith made several major changes to the King James Version of Matthew 24, a fact noted by Mormons themselves. According to the Church of Jesus Christ of the Latter Day Saints, Matthew 24 of the King James Version contains 1050 words, while JS-M contains some 1500 words (1). This suggests that much was added to the original by Smith.
The JS-M work can be divided into three parts. Part 1 (verses 1-4) is the introduction, which focuses on Jesus’ disciples and their questions, Part 2 (verses 5-21) focuses on prophecies about the destruction of Jerusalem, and Part 3 (verses 21-55) focuses on prophecies about the latter days, the end of the world, and the Second Coming of Jesus. Thus, for Mormons, Matthew’s gospel is important because in it Jesus, prior to his crucifixion and resurrection, answered the questions his disciples asked concerning the destruction of the temple in Jerusalem, the scattering of the Jews, and events that would occur prior to Jesus’ Second Coming. These were apparently of great interest to Smith too given the significant changes and additions he made to the original biblical text. Mormons believe that God revealed to the Joseph Smith what Jesus had initially told his disciples concerning these things, and thus it is inspired scripture.
1. The Church of Jesus Christ of Latter Day Saints. Joseph Smith-Matthew: Student Manual. Available.