John the Baptist was the son of the priest Zacharias and Elisabeth, born to them in their old age after Elisabeth had been barren; an angel appeared to Zacharias in the temple, told him his wife would bear a son, and directed that the child be named John (Luke 1:5-13). His coming was foretold by the Old Testament prophets Isaiah and Malachi, and on the American continent by Lehi and Nephi, who said a prophet would prepare the way before the Messiah, baptize in Bethabara beyond Jordan, and baptize the Lamb of God who would take away the sins of the world (1 Nephi 10:7-10; 2 Nephi 31:4).
He was baptized in childhood and ordained by an angel at eight days old, not to the priesthood but to his calling to prepare the way of the Lord (D&C 84:28). Called an Elias, one who prepares the way for someone greater, he said of Christ, “he that cometh after me is mightier than I” and “He must increase, but I must decrease” (Matthew 3:11; John 3:30). Herod imprisoned John for condemning his marriage to Herodias, his brother Philip’s wife, and at Herod’s birthday had him beheaded after Herodias’s daughter, prompted by her mother, asked for his head (Matthew 14:3-11).
As a resurrected being, John appeared to Joseph Smith and Oliver Cowdery on May 15, 1829, and conferred on them the Aaronic Priesthood, which holds the keys of the ministering of angels and of baptism by immersion for the remission of sins (D&C 13).