What does Mark 15:17 mean?

It appears that the soldiers are dressing Jesus as a prince but with shoddy duplicates. We don't know what kind of thorn bush makes the crown, but it may mimic the leafy wreath given to a minor landowner. While John says the soldiers use a "purple robe" (John 19:2), and Mark says a "purple cloak," Matthew says a "scarlet robe" (Matthew 27:28). Part of this is the subjective nature of describing colors—the color "orange," for instance, was considered "reddish yellow" until the fruit became known. It may be that the soldiers use what they have lying around to substitute for the royal purple robe of a prince.

The Gospel writers concentrate on different aspects of Jesus' life and ministry. Luke explains that Pilate has Jesus beaten and tortured in hopes the pain and humiliation will appease the Sanhedrin and convince them to release Jesus (Luke 23:22). John explains that after the solders put the crown of thorns and the robe on Jesus, Pilate leads Him out to the crowd (John 19:4–5). Surely, Pilate hopes, the Jewish leaders will agree that a public display of powerless humiliation is enough.

But Pilate is no hero in this story. History describes him as ruthless, vicious, and violent against the guilty and the innocent. In this battle between Jesus and the Sanhedrin, he wins either way. If he kills Jesus, he will placate the people who threaten to riot. If Jesus defends Himself and Pilate finds Him innocent, Pilate can charge the members of the Sanhedrin with calumny—false charges—and give them the same punishment they demand for Jesus. Pilate can crucify the chief priests, elders, and scribes.

This instinct to use violence and power is the exact opposite of what Jesus taught the disciples godly authority looks like. After James and John ask Jesus to give them positions of influence in His kingdom, Jesus tells the disciples they must not exercise authority over their charges like the Gentiles do (Mark 10:42–44). The first must be as a servant, a slave to those he is responsible for. "For even the Son of Man came not to be served but to serve, and to give his life as a ransom for many" (Mark 10:45).