The Transformed Mind
Let's take a look at Romans 12:2 in a couple of different translations:
"Don’t copy the behavior and customs of this world, but let God transform you into a new person by changing the way you think. Then you will learn to know God’s will for you, which is good and pleasing and perfect." Romans 12:2, NLT
"Do not be conformed to this world (this age), [fashioned after and adapted to its external, superficial customs], but be transformed (changed) by the [entire] renewal of your mind [by its new ideals and its new attitude], so that you may prove [for yourselves] what is the good and acceptable and perfect will of God, even the thing which is good and acceptable and perfect [in His sight for you]." Romans 12:2, Amplified Bible, Classic Edition
The word transformed indicates a process, a metamorphosis, or a progressive change of the form or nature of a thing or person into a completely different one, by natural or supernatural means.
Our mind (Greek word psuche’) is the component of our design where we house and process our thoughts, our feelings, our emotions, our intellect, our imaginations, and our will. Psuche’ is the root word for psychology, or the study of our mind.
When we experience the new birth, our spirit is changed instantly and our relationship and fellowship with our Creator God -- once severed and inoperable -- is restored and is fully engageable immediately. However, allowing our mind to be reprogrammed and to think differently is a process. We are in charge of that process. We get to choose -- in fact, we must choose -- what we allow to become a part of our thoughts, our imaginations, our databank, and our memory that we use to measure and to judge the things of life we encounter.