Christianity does not begin with a book that became a best seller. It does not really even begin with Jesus, although obviously, it is dependent on the life, death and resurrection of Jesus and the religious movement which followed. Rather, it begins with a slightly eccentric figure: John the baptiser, who creates a storm of interest when he begins preaching in the wilderness. It was time, he announced to his countrymen, that they must repent of their sins, be baptised and get ready for the coming of the Messiah who will be far greater than John himself (Mk 1:7).
Mark, who wrote this gospel, notes that John’s role is like that of the prophet Isaiah (Isaiah 40:3). His prophetic preaching is presented as the fulfillment of Malachi 3:1 which warned that Elijah would come again just before God judged Israel. Even his eccentric appearance (a coat of camel’s hair and his eating locusts and honey), is a reference to how John is the fulfillment of that eerie figure Elijah. Mark’s point is simple: John, who baptizes, is the fulfillment of OT expectations and his arrival marks the commencement of the long waited age of the Messiah. Although John baptizes with water, this Messianic figure who comes after him will baptize them with the Holy Spirit, and this will mark the beginning of a new age: the age of the Messiah. But what does John demand of the crowd? Repentance: they need to confess their sins before they are baptized. John’s message, like Jesus (Mk 1: 14-15), makes demands before baptism is administered. Otherwise, it would be merely ‘cheap grace’ as Dietrich Bonhoeffer would say later.