I want to draw attention to a clause that is often overlooked when reading Mark:
‘Now after John was arrested.’
While we may argue whether Jesus’ ministry starts at his baptism or with his temptation, the start of his public ministry is clearly described here. And this start didn’t occur until after John the Baptist had been arrested.
This doesn’t really make sense to us (and, for other reasons, it didn’t make sense to John or the disciples either) : why would Jesus wait until John was arrested before beginning his ministry? It seems like Jesus and John would make a pretty good team! Crowds were drawn to John, and we’ll see soon enough that crowds were drawn to Jesus. They were proclaiming a similar message (compare v. 15 and v. 4). John had no problem playing second fiddle to Jesus (v. 7-8). John, while he suffered his own doubts, would have been much more adept at following Jesus than most, if not all, of his disciples were. So what gives?
The answer is one that we should all take to heart: John had served his role (and faithfully at that) in the grand story of God and his redemption of the world. John is not the main character–that was never the plan. He had done his job well, proclaiming baptism and repentance of sins (v. 4), but now Jesus came proclaiming the gospel (v. 14). John moves into the background so that way there is no division of attention–Jesus demands our full attention, not to be split with John.
John had served his role–the time he spoke about is now fulfilled and the kingdom of God is finally here after breaking into human history at Jesus’ baptism. In our own lives, too often we are not content to serve in the role that God has given us. Wherever we are, whatever we do, whether the stage is big or small, we are to point to Jesus.