We have seen that an important statement of faith in the kerygma was that in Jesus Christ, the promises and prophecies of the Jewish Scriptures were fulfilled. In 1:2 Mark takes a prophecy from Malachi 3: 1 and follows it, in 1:3, with another from Isaiah 40:3, to introduce the reader to John the Baptist. The last verse but one of the Old Testament says, 'But before the great and terrible Day of the Lord comes, I will send you the prophet Elijah.' The reference in 1:6 to the clothing and food of John the Baptist and to his being in the desert (l: 4) are significant because they reflect the stories of Elijah (2 Kings 1:8, 1 Kings 17:5-6). Later in the gospel, Jesus says that Elijah had come (9: 13), obviously referring to John, who had in a spiritual sense fulfilled the prophecy in Malachi 4:5. Mark portrays John as the prophet who would come before the end of the present evil age and the Day of the Lord. In his preaching John demanded that his hearers should turn away from their sins and return in total obedience to God, so that they might be forgiven on the Day of Judgement, the Day of the Lord. Mark's account is so terse that we have to turn to the fuller accounts in Luke 3 :7-9 and Matthew 3 :7-10 to find out that John's urgent call to his hearers to change their way of life radically came from his conviction that the 'great and terrible Day of the Lord' was imminent; time had almost run out. Those who did not repent would soon be destroyed because of their sins.

To separate the genuinely repentant from the unrepentant, John baptized them in the river Jordan (1:4-5),

 initiating something new in Judaism. Gentile proselytes who wanted to commit themselves fully to Judaism were baptized and there were forms of ritual washing amongst the Pharisees and Essenes, but the idea of those who were already Jews accepting the baptism of immersion in the river, which John practiced, was entirely new. John was separating those who were genuinely God's people from those who thought that physical descent from Abraham would assure them of forgiveness on the Day of Judgement (Luke 3 :7-8).

Mark omits the details of John's ministry which are given by Luke and Matthew and moves swiftly to the climax of John's message, in 1:7-8. John not only announced the imminent Day of the Lord but the expected arrival of God's representative who would inaugurate God's Judgement and manifest God's rule over the universe. The word 'Messiah' is not used and the Greek in 1:7 just means that someone much greater than John is about to come, but what is said in 1 :7-8 leaves the reader in no doubt that the one for whom John is waiting will be like no one the world had ever seen before. John spoke and acted with all the God-given assurance and compulsion that we see in the Old Testament prophets, but compared with the one whose coming he prophesied, John would be utterly insignificant, not even fit to be his slave. In Mark's account of John the Baptist and his work, he looks back from the knowledge of the early Church that John's prophecy was fulfilled in Jesus Christ.