To understand the role of John the Baptist in Mark’s gospel we need to remember the hope and aspirations of the people of Israel in the pre-Christian era. For more than three hundred years before the coming of Jesus there was no prophet in Israel. This situation is lamented in Psalm 74: 9 “there is no longer any prophet … among us …” (Cf. also Dan 3: 5). Yet, people maintained the hope that God would intervene once again and send his true prophet who would signal surely and effectively the coming of the Messiah (Cf. Deut 18: 15; Acts 7: 37). Many expected the prophet Elijah to return before God’s final intervention for the liberation of the people. We can see traces of this expectation reflected in the Old Testament passages such as: – Malachi 3: 1; 4: 5-6; Sirach 48: 9-10; Isaiah 40: 3. Mark sites two of these texts (Mal 3: 1; Is 40: 3) to introduce John the Baptist and his role preparatory to the advent of the Messiah. Mark’s description of John’s clothing is meant to evoke the image of Elijah (2 Kings 1: 8). In Mark 9: 9-13 John the Baptist is identified with Elijah (Cf. Mt 11: 14).
In Isaiah 40: 3 the second exodus through the wilderness is announced. It is similar to the announcement made by God in Exodus 23: 20 of his messenger leading the people of Israel through the wilderness to the land of freedom. Mark thus shows that John the Baptist is the messenger of the new and decisive moment of history, and that he is the expected prophet who will be the fore-runner of the Messiah. John’s baptism of repentance and his message unmistakably reveal his preparatory role and they point forward to the one coming after him. Besides, “Baptism with the Holy Spirit” mentioned in Mark 1: 8 seems to refer to the fresh outpouring of the Spirit in the messianic times spoken of in terms of a second exodus (Is 32: 15; 44: 3). John the Baptist is important in Mark’s gospel not for his own sake but for his role as the fore-runner of the Messiah. John the Baptist fulfills his function by his prophetic appearance, by his word, by his baptism of repentance, and later by his own death (Cf. Mk 6: 14-29).
John’s call to repentance or the baptism of repentance was in line with the prophetic ministry in Israel. Prophets are catalysts. They indicate God’s coming, his judgment, and they awaken a sense of his presence in history. True prophets emphasize the centrality of God as John the Baptist does with regard to Jesus.