Romans 12:2
“And do not be conformed to this world, but be transformed by the renewing of your mind, that you may prove what is that good and acceptable and perfect will of God.”
The idea is rather simple: We are to allow the transforming Word of God to work within us and produce outward results, instead of permitting external pressures to shape us.
If we meditate on God's Word daily, it will influence our thoughts and help us grow to be more like Jesus Christ. Then we will act in a manner that pleases Him.
Pressures of the world will continue to try to shape our character, but they will not succeed if God's Word is changing us from within.
The Truth
"But we all, with unveiled face, beholding as in a mirror the glory of the Lord, are being transformed into the same image from glory to glory, just as by the Spirit of the Lord." (2 Corinthians 3:18)