but be transformed by the renewing of your mind,
so that you may prove what the will of God is,
that which is good and acceptable and perfect. (NASB)
The second phrase moves on from Paul’s negative command (renounce the world) to a positive one: Commit to a lifetime of retraining your mind so that you live by the truth, which has the power to transform you. That is perhaps the best way to interpret this phrase.Be transformed
The transformation from fledgling believer to mature Christian happens over a lifetime in the progression toward Christlikeness. The Greek verb is metamorphoo, from which we get the English term metamorphosis that describes the transformation of a caterpillar into a butterfly. A similar transformation is from acorn to oak tree. The nature of the entity remains the same but takes on an entirely different form.
The same word is used of Christ’s Transfiguration. Just as the oak tree is hidden in the acorn, the glory of the Son of God was hidden when Jesus walked the earth. That glory was briefly revealed to three of his disciples on the mountain “when his clothes became radiant, intensely white, as no one on earth could bleach them” (Mark 9:2–3). His resplendent glory will be on full display when he returns. Our glory will also be on display.
Who does the transforming? God, but we believers position ourselves to let him do the transforming (this is implied by Paul’s use of the passive voice). God provides his holy word and the Holy Spirit. We renew our mind by applying his word to our mind and heart and yielding to the Holy Spirit. As the acorn needs soil and water to sprout into an oak tree, we need word and Spirit to mature. Believers who neglect these essentials risk violation of Paul’s first command in this verse.The renewed mind
A Christian with a renewed mind loves God—his essence, his character, his works, his plan for humanity’s future. When God became man, Jesus announced himself as the Light. But the majority of people rejected him, not wanting their evil deeds to be exposed in the light (John 3:19–20). “Whoever lives by the truth comes into the light,” says John in verse 21. That verse is a good description of Christians who are renewing their minds: they live by the truth, seeking the light.
Whereas the world lives in darkness, the people of the Lord cherish the light. Darkness and light differentiate the world that is passing away from the world that is to come. Charles Swindoll lists several questions that people in these two worlds answer very differently:
What makes a man or woman great?
Who or what determines right and wrong?
How should one respond to an offense?
What determines a person’s worth?
Why do kind people suffer while cruel people prosper?
Douglas Moo says Paul uses the word mind to describe a person’s “practical reason” or “moral consciousness.” Thoughts from the renewed mind always lead to renewed actions. You can recognize Christians with renewed minds by watching what they do and say. They think what Christ would think and do what Christ would do.Renewed by the Spirit
The Greek word translated renewal is also found in Titus 3:5 where the focus is on the initial stage of renewal: “He saved us through the washing of rebirth and renewal by the Holy Spirit.” Only Christ and the Holy Spirit could execute that stage. So a process that was quick-started by God is now a cooperative activity as we commit to a lifetime of renewing our minds in dependence on him. Rebirth gives way to sanctification, an ongoing, cooperative activity of God and believer.
All who believe in Christ have the Spirit of Christ (Romans 8:9). Now we have a choice—to set our minds on the things of the flesh or on the things of the Spirit. Paul says those who set their minds on the things of the Spirit live according to the Spirit (8:5). Action follows thought.
Want to have the attitude of Christ? Check out Philippians 2:1–8 and do what it says.
Want to have the mind of Christ? Put your mind on Christ (Colossians 3:1, and note the resulting actions in the rest of that chapter).
Want to be like Christ? See 2 Corinthians 3:18. Gaze on the glory of Christ, and the Spirit will transform you (it’s the same Greek word) into his image. Fix your eyes on him (Hebrews 12:2).
For a close parallel to these beginning verses of Romans 12, see Ephesians 4:20–24.