Romans
King James Version (KJV)

“And be not conformed to this world: but be ye transformed by the renewing of your mind, that ye may prove what is that good, and acceptable, and perfect, will of God.”
King James Version (KJV)
12:2 And be not conformed - Neither in judgment, spirit, nor behaviour. To this world - Which, neglecting the will of God, entirely follows its own. That ye may prove - Know by sure trial; which is easily done by him who has thus presented himself to God. What is that good, and acceptable, and perfect will of God - The will of God is here to be understood of all the preceptive part of Christianity, which is in itself so excellently good, so acceptable to God, and so perfective of our natures.
Ro 12:2 And be not conformed to this world. The spirit of the world is opposed to that of Christ. Satan is "the Prince of this world (Joh 12:31 14:30 16:11). Christ died "to deliver us from this present wicked world" (Ga 1:4). Hence the service of Christ renders necessary a refusal to fashion ourselves after its ways. But be ye transformed. Instead of following the ways of the world, the Christian must be "transformed", changed into a new form of life by the renewing of your mind, by having a new spirit, and "walking after the Spirit" (Ro 8:1,4 Ga 5:16,25). That ye may prove. Demonstrate, show forth. The saint, transformed, renewed, will show forth in his life "the will of God".