Mormonism and Nicene Christianity

Mormonism and Nicene Christianity (often called mainstream Christianity) have a complex theological, historical, and sociological relationship. Latter-day Saints express their doctrines using biblical terminology. They have similar views about the nature of Jesus's atonement, bodily resurrection, and Second Coming as mainstream Christians. Nevertheless, most Latter-day Saints do not accept the doctrine of the Trinity as codified in the Nicene Creed of 325 and the Nicene-Constantinopolitan Creed of 381. Although Latter-day Saints consider the Protestant Bible to be holy scripture, they do not believe in biblical inerrancy. They have also adopted additional scriptures that they believe to have been divinely revealed to Joseph Smith, including the Book of Mormon, the Doctrine and Covenants, and the Pearl of Great Price. Latter-day Saints practice baptism, confirmations and celebrate the sacrament of the Lord's Supper, but they also participate in other religious sacraments.

Focusing on differences, some Christians consider Mormonism non-Christian; others, focusing on similarities, consider it to be a Christian denomination. Opinions differ among scholars of religion on whether to categorize Mormonism as a separate branch of Christianity or as a "fourth Abrahamic religion" (alongside Judaism, Christianity, and Islam). Latter-day Saints do not accept non-Mormon baptism and most non-Mormon Christians do not accept Mormon baptism. Latter-day Saints regularly proselytize individuals within the Christian tradition, and some traditional Christians, especially evangelicals, proselytize Latter-day Saints. Some view Mormonism as a form of Christianity, but distinct enough from traditional Christianity so as to form a new religious tradition, much as Christianity is more than just a sect of Judaism.

The early Mormonism that originated with Joseph Smith in the 1820s shared strong similarities with some elements of 19th-century American Protestantism. Latter-day Saints believe that God, through Smith and his successors, restored various doctrines and practices that were lost from the original Christianity taught by Jesus. For example, Smith, as a result of his "First Vision", primarily rejected the Nicene doctrine of the Trinity and instead taught that God the Father, his son Jesus, and the Holy Ghost are three distinct "personages". While the largest Mormon denomination, The Church of Jesus Christ of Latter-day Saints (LDS Church), acknowledges its differences with mainstream Christianity, it also focuses on its commonalities such as its focus on faith in Jesus, following the teachings of Jesus, the miracle of the atonement, and many other doctrines.