A dispensation of the gospel is a period of time on earth when the darkness of apostasy is dispersed, when authorized servants dispense God's word and administer saving ordinances. Elder David W. Patten of the Quorum of Twelve explained that a dispensation of the gospel "is power and authority to dispense the word of God, and to administer in all the ordinances thereof" (History of the Church, 3:50). Adam opened the first dispensation of the gospel. After periods of apostasy, other dispensations were opened by Enoch, Noah, Abraham, Moses, and Jesus Christ.
Joseph Smith was the chosen prophet of the latter days even before he was born. He was like the prophet Jeremiah, to whom the Lord said, "Before I formed thee in the belly I knew thee; and before thou camest forth out of the womb I sanctified thee, and I ordained thee a prophet unto the nations" (Jeremiah 1:5). So it was with Joseph Smith. "At the general and grand Council of heaven," taught Joseph, "all those to whom a dispensation was to be committed, were set apart and ordained at that time, to that calling (Discourse given by Joseph Smith on May 12, 1844, in Nauvoo, Illinois; reported by Samuel W. Richards; quoted in The Words of Joseph Smith, ed. Andrew F. Ehat and Lyndon W. Cook , 371).