In St. Peter's great confession in Matthew 16, he correctly and with great intuitive power shows that he understands who Jesus is. He's not simply Elijah or one of the prophets, not just another great teacher, but the Messiah of God, the one, the deliverer of whom all the prophets spoke.

Well, how would this accomplish anything? How could this be anything but a repeat of all of the sad, fallen Jewish heroes of the past who were crushed by more powerful enemies?
Because this Messiah would defeat the powers of the world, not by fighting them on their own terms, but by absorbing them, taking all the aggression they could muster and then swallowing them up in the ever-greater forgiveness of God.

What becomes clear in the Gospels is that this is God's way of battling evil. The world is transformed through the power of suffering love. That is the whole message of the crucified Messiah.
"The world is transformed through the power of suffering love."
- Father Robert Barron