What is the Mormon source of truth? For Christians, our one and only source for truth is the Bible, but for Mormons, they have 10 sources of truth: Book of Mormon, Doctrine and Covenants, Pearl of Great Price, Inspired Version of the Bible, Book and magazines published by the LDS Church, Theological Books written by key LDS apostles & prophets in the LDS Church, Temple rituals, and personal testimony by the "Holy Ghost". Because they have so many sources that define Mormon doctrine, one must learn how to "authenticate" any book or publication by the LDS standard before one can use it to define Mormon doctrine when witnessing to Mormons.