If we desire that there be no boasting except in the cross, then we must live near the cross--indeed we must live on the cross. This is what Galatians 6:14 says: "Far be it from me to boast except in the cross of our Lord Jesus Christ, by which the world has been crucified to me, and I to the world." Boasting in the cross happens when you are on the cross. Is that not what Paul says? "The world has been crucified to me, and I [have been crucified] to the world." The world is dead to me, and I am dead to the world. Why? Because I have been crucified. We learn to boast in the cross and exult in the cross when we are on the cross. And until our selves are crucified there, our boast will be in ourselves.
Don't boast in anything except in the cross. How shall we become so radically cross-exalting? How can we become the kind of people who trace all our joy back to joy in Christ and him crucified? Answer: The old self that loves to boast and exult and rejoice in other things died. By faith we are united to Christ. His death becomes the death of our self-exalting life. We are raised with him to newness of life. What lives is a new creature whole single passion is to exalt Christ and his cross. To put it another way, when you put your trust in Christ, your bondage to the world and its overpowering lure is broken. You are a corpse to the world, and the world is a corpse to you. Or to put it positively, according to verse 15, you are a "new creation." To the you is dead. A new you is alive. Ad the new you is the you of faith. And what faith does is boast not in the world, but in Christ, especially Christ crucified. This is how you become so cross-centered that you say with Paul, "I will not boast, except in the cross of our Lord Jesus Christ." The world is no longer our treasure. It's not the source of our life or our satisfaction or our joy. Christ is.
~John Piper, Don't Waste Your Life
