Chapters 7 & 8 alternate stories about the Pharisees and disciples’ misunderstandings with stories about Jesus’ miracles. It’s a pretty big contrast to see the Pharisees and disciples (and even ourselves) be worried about very small things while Jesus is feeding four thousand people, making the blind see, the deaf hear and casting out demons. Jesus’ words to Peter in 8:33 (“For you are not setting your mind on the things of God, but on the things of man.”) summarize the primary difference between the Pharisees and the true followers of Jesus. Jesus warns his disciples in v. 14-21 to watch out for the teaching/perspective of the Pharisees and of Herod, but they are too caught up in worldly worries to understand his point. He then tells his disciples what it looks like to have their mind on the things of God- it looks like sacrificing your entire life to pursue God.
This passage reminds me of Romans 8:5 “For those who are according to the flesh set their minds on the things of the flesh, but those who are according to the Spirit, the things of the Spirit.” And Philippians 4:8 that gives us even more help in knowing what to think about. As someone who struggles to turn my brain off, focusing my thoughts on God has a significant impact on my spiritual growth and other areas of my life.