One of the difficulties of going through the whole Bible chapter by chapter is that some chapters are just too big. Mark 6 (link) is just such a chapter. We have the diversity of events that range from Jesus teaching at Nazareth to the feeding of the 5,000, to walking on the water, and then back to more teaching and healing.
There's a lot here. You should read it more than twice. I would draw your attention to the juxtaposition of the stories of Mark 6:7-13 and Mark 6:14-29. These two stories about one time in which Jesus sent out the Twelve to preach and the execution of John the Baptist are put together.
We would tend to think they ought not go together. After all, one is a story of great triumph and the other is the sad tale of a preacher killed for his stand on righteousness. If Jesus is looking to recruit disciples, then only one story should be included here: the story of triumph! The news that not only Jesus but His disciples can heal, drive out demons, and preach would surely attract a good many folks to the cause.
That's worth doing, right? We want to do whatever it takes to draw in new disciples, so we should emphasize the positive possibilities of life as a Christian. Any downside should get mentioned later, if at all. After all, only John the Baptist has been executed at this point in the narrative, so there's no cause for alarming other disciples until we see if the pattern of life will really continue.
Except in the inspiration of the text, Jesus does not do that. He places these two situations right beside each other, even though the text itself is clear that the execution of John had happened some time before. There are good things and bad things that happen in the life of following Christ, and we do not do anyone any favors by hiding those.
What happens? The life of discipleship is a life of obedience to Christ. It is not simply about the power that comes through the Holy Spirit. In fact, life is barely about that—the primary work of the Holy Spirit in the life of a Christian is the ability to live that obedience.
In some ways that obedience is an outward obedience: go here, do this, preach that. That obedience is to treat this person with grace or to show that person love, as this is the command of God that we do so.
Other ways show up that the obedience is internal. It is common to think of the self-sacrificial ideas that are trumpeted in modern American Christianity: the person who moved from the 4,000 square foot home to the 2,000 square foot home to give more money, the missionary, the school teacher—all of these do show a level of self-sacrifice. There is more, though, at stake, and it is this more that truly demands the aid of the Spirit of God.
One key point of understanding the Bible and the Christian faith is realizing that everything from the end of Genesis 3 through Revelation 20 reflects a world that is marred and wrecked by sin. The very nature of mankind is harmed by sin—we are born with tendencies to sinful behavior. Each one of us carries this issue, though it may come to the surface differently for one than for another.
The Spirit of God is what gives us the ability to push those tendencies toward more godly usage. We see example after example in life and in the Bible of people who would not do so: David with his many wives; Samson with his issues; the Israelites; even Peter, Barnabas, and others show how many ways sin rises up and pulls people away from living in obedience to God.
A huge portion of the life of a disciple is learning to let the Spirit of God rebuild our hearts and minds to not seek those sins any longer. That is a substantial part of what being transformed by the renewing of our minds (Romans 12:1-2) is all about.
The warning of Mark 6 is this: some will live life to satisfy the nature all humanity is born with. Herod was one of these—his desire was for his brother's wife, and he took her. John called out that this was sin. It was not the only thing John called sin, for though we lack a large record of his preaching, he also called out religious pretense and social injustice in his days at the Jordan.
He hit on one big nerve, though, and it put him in prison first and cost him his life later. That's the path that discipleship may take: those who follow human nature will rise up against those who strive to follow the Spirit of God. As Christians, either be ready to deal with it or be ready to deal with it, because it has been this way for two millennia. It does not change until The Millennium.
Today's Nerd Note: The Feeding of the 5000 is recorded in Mark 6:33-44, and also in the other 3 Gospels. It's a rare event in that: most of John outside of the Passion Week differs radically from Matthew, Mark, and Luke, in terms of narrative flow.
One should consider how important that makes this moment. I think John's recollection that the people intended after this to make Jesus king by force is why it is important: He could have ruled that way rather than taking the road to the Cross. The world would have allowed that, approved that, followed that. Instead He met the greater need: not merely a good life now but eternal life through His sacrifice.
Also, consider this: believing that God is the author of Scripture means that we do not count one set of the words as more important than any others. In other words: how the narrative is arranged is as much a work of God as the specific words of Jesus spoken and recorded. It is reasonable to examine those types of factors to seek clear meaning in the text.