We have but fragmentary and imperfect accounts of John the Baptist or John the Baptizer in the Gospels. (The Eastern Orthodox also refer to him as John the Forerunner because he was the forerunner of Christ.) According to Catholicism and Eastern Orthodoxy, he was the last of the prophets. He was of priestly descent. His father, Zacharias, was a priest of the course of Abia (1 Chr. 24:10), and his mother, Elisabeth, was of the daughters of Aaron (Luke 1:5). The mission of John was the subject of prophecy (Matt. 3:3; Isa. 40:3; Mal. 3:1). His birth, which took place six months before that of Jesus, was foretold by an angel. Zacharias, deprived of the power of speech as a token of God's truth and a reproof of his own incredulity with reference to the birth of his son, had the power of speech restored to him on the occasion of his circumcision (Luke 1:64). After this no more is recorded of him for thirty years than what is mentioned in (Luke 1:80). John was a Nazarite from his birth (Luke 1:15; Num. 6:1-12). He spent his early years in the mountainous tract of Judea lying between Jerusalem and the Dead Sea (Matt. 3:1-12).
At length he came forth into public life, and great multitudes from "every quarter" were attracted to his message. The sum of his preaching was the necessity of repentance. He denounced the Sadducees and Pharisees as a "generation of vipers," and warned them of the folly of trusting to external privileges (Luke 3:8). "As a preacher, John was eminently practical and discriminating. Self-love and covetousness were the prevalent sins of the people at large. On them, therefore, he enjoined charity and consideration for others. The publicans he cautioned against extortion, the soldiers against crime and plunder." His doctrine and manner of life roused the entire south of Palestine, and the people from all parts flocked to the place where he was, on the banks of the Jordan. There he baptized thousands unto repentance (see AEnon).
The fame of John reached the ears of Jesus in Nazareth (Matt. 3:5), and he came from Galilee to Jordan to be baptized of John, on the special ground that it became him to "fulfil all righteousness" (3:15). John's special office ceased with the baptism of Jesus, who must now "increase" as the King come to his kingdom. He continued, however, for a while to bear testimony to the Messiahship of Jesus. He pointed him out to his disciples, saying, "Behold the Lamb of God." His public ministry was suddenly (after about six months probably) brought to a close by his being cast into prison by Herod, whom he had reproved for the sin of having taken to himself the wife of his brother Philip (Luke 3:19). He was shut up in the castle of Machaerus, a fortress on the southern extremity of Peraea, 9 miles east of the Dead Sea, and here he was beheaded at the instigation of Herodias; later tradition also implicates Salomé. His disciples, having consigned the headless body to the grave, went and told Jesus all that had occurred (Matt. 14:3-12). John's death occurred apparently just before the third Passover of Jesus' ministry.
Jesus himself testified regarding John that he was a "burning and a shining light" (John 5:35). The Eastern Orthodox believe that John was the last of the Old Testament prophets, thus serving as a bridge figure between that period of revelation and Jesus. They also embrace a tradition that, following his death, John descended into Hell and there once more preached that Jesus the Messiah was coming.
The Eastern Orthodox Church remembers Saint John the Forerunner on six separate feast days, listed here in order of the church year which begins on September 1:
Unificationists regard John the Baptist as "the greatest man born of woman" (Mt 11:11), yet they criticize him for his "failure" to get the Jewish people to believe that Jesus was the Messiah.
In Gnosticism, John the Baptist was a "personification" of the Old Testament prohphet Elijah. According to Gnostic theology, John the Baptist was a prophet from the Old Testament who did not know the True God (the God of the New Testament, as opposed to the God of the Old Testament — see the article on Gnosticism for details), and thus had to be re´ncarnated. As predicted by the Old Testament prophet Malachi, Elijah must "come first" to herald the coming of Jesus Christ. John the Baptist indeed does "come first" before Jesus in all four Gospels, however, in the canonical Christian view, John the Baptist is not Elijah. Indeed he directly denied being Elijah according to the Gospel of John 1:20: when the jews ask him if he is the Messiah, he empathically denies this. Then they ask him if he is Elijah, to which he answers "I am not.". According to canon, John does fulfill the prophesy of Malachi, but is not the prophet Elijah re´ncarnated.