Cynthia Nielson at Per Caritatem writes:

Have you ever wondered why the soldiers chose a crown of thorns? After all, they could have constructed the crown from a number of other materials. Yet, the crown of thorns seems purposed, that is, it draws us back to the Genesis and the series of curses that resulted when our first parents fell. “Cursed is the ground because of you; in pain you shall eat of it all the days of your life; thorns and thistles it shall bring forth for you” (Gen 3:17-18). As Jesus begins to walk the path that leads to his death by crucifixion, we have a glimpse here of how he, the true guiltless Man, will take the curse, our curse upon Himself. The scene is shot through with irony-Pilate, the image of a false and corrupt “king,” presenting the true King as a helpless prisoner and eventually condemning Him to die. Likewise, we see Jesus, the Lord of creation, the perfect image of God, who unlike Adam and Eve, listened the voice of the Father in humble obedience even to the point of death on a Cross-this Jesus, Pilate proclaims is the true man (talk about meanings going beyond the intention of the author/speaker), and indeed He is-the icon of God who makes the invisible God visible, who opens blind eyes, softens hard hearts and who gives life to the dead. Yet, the One through whom all things were made and who, came to His own, finds His own in rebellion against Him. In fact, they even weave together a crown of thorns and dress Him in a purple robe to mock Him. What is our Lord’s response to this? Does He lash out and call down legions of angels to wipe out the rebels? No. The innocent, yet true King, crowned with signs of creation’s curse, stands silent and walks the path that was both His destiny and our blessing. How shall we answer Pilate’s question, “What is truth?” Ironically, Pilate answered it himself: “Behold the Man!”