As the Christ, Jesus had to lay down His life; He had to sacrifice Himself so that all who trust in Him will live. This is not the thinking and the action of the world, nor of the god of this world.
Unbelievers - if you want to save your life by living it your way, rather than the way the Lord calls you to live it, you will lose it. But if you lay down your life; if you deny yourself and follow Jesus, you will gain it. Consider what the world will cost you, and choose life instead.
Believers, take the warning from this passage too. Peter was a believer and yet his heart and mind were more aligned with Satan than with Jesus in the things he said in this passage. We need to let go of the world and keep our hearts and minds on things above!