During Christ's mortal ministry in Jerusalem, He organized a church to ensure that His truths would be taught after His departure from the Earth. He called 12 apostles and gave them priesthood authority-or the authority to act in God's name-to conduct the affairs of His church (Mark 3:14-19; John 15:16). He also called an additional 70 disciples and gave them authority to preach His doctrine (Luke 10:1). Finally, Christ established ordinances, such as baptism, that were to be performed in a specific manner within His church. The New Testament is a record of Christ's ministry in Jerusalem. Mormons, while accepting the Bible, also believe that Christ ministered to the peoples of the ancient Americas. The Book of Mormon is a record of this ministry. It covers a span of time from roughly 600 B.C.E. to 424 C.E., and its central event is Christ's personal ministry in the Americas shortly after his resurrection in Jerusalem. Just as in Jerusalem, Christ called 12 disciples and gave them the priesthood authority to act in His name (3 Nephi 12:1; 3 Nephi 28:36-37), instituted ordinances such as baptism (3 Nephi 11:23-28, 3 Nephi 18:1-11), and established His church with the mandate that it be called after His name (3 Nephi 27:1-5, 8).
A short while after the establishment of Christ's church in both Jerusalem and the Americas, Christ's teachings were rejected, His followers persecuted, and His church ultimately corrupted. Eventually, the church lost its priesthood authority, and, consequently the true church of Christ was lost from the Earth. Mormons refer to this period of history as the Apostasy. In this way, Christ's church followed the biblical pattern established by Adam, Noah, Abraham, and Moses. Each of these prophets taught Christ's truth and was accepted for a time. Eventually, though, the prophets were rejected and the truth they taught was lost. However, it is important to note that after each rejection of truth, God called another prophet to restore that truth. Mormons believe this Apostasy was overcome, and Christ's true church restored through the modern-day prophet Joseph Smith.
This restoration began in the spring of 1820 in upstate New York. At the age of 14, Joseph Smith found himself confused by the contradictory teachings of different religions. One morning he went to a secluded grove of trees and knelt in prayer, asking for divine guidance as to which church he should join. In response to his prayer, God and Christ appeared to him and counseled him not to join any church. Rather, they explained that he would play a role in restoring Christ's church to the Earth (Intellectual Reserve, 2004). In September 1827, an angelic messenger revealed to Joseph Smith the location of ancient records containing the Book of Mormon and commissioned Smith to translate them. In May 1829, John the Baptist, and later the apostles Peter, James, and John, appeared to Smith and gave him priesthood authority to act in Christ's behalf. Finally, on April 6, 1830, the Church of Jesus Christ of Latter-Day Saints was officially organized in Fayette Township, New York. After Smith's death in 1844, Brigham Young followed as the second prophet and president of the church. From that time forward, the death of one prophet has always been followed by the calling of another, each of whom has possessed the same priesthood authority given to Joseph Smith, and has received divine revelation as to the leadership of the church and the instruction of its members. Mormons believe that, in this way, Christ continues to guide His church and communicate with His followers. In Mormonism, then, the church becomes a "living" entity. Simply put, the heavens are very much open, and God is in constant communication with His children through His chosen prophet. This belief is, perhaps, best summarized in the ninth article of faith which reads, "We believe all that God has revealed, all that He does now reveal, and we believe that he will yet reveal many great and important things pertaining to the Kingdom of God" (Intellectual Reserve, 1981).