|Romans 12:2 (NASB)|
First, we must see what the passage implies. It implies that our minds need to be renewed. It implies that there is something fundamentally wrong with our minds and that if that problem is not resolved we cannot do what is good and acceptable in the eyes of God. That's not just a little problem. It's a rotting mental disease!
In fact, just a bit earlier in Romans Paul points out that the mind that is not renewed is more than just diseased, it's positively pathological.
The mind apart from Christ is death, hostile toward God, rebellious, unable to even do good or please God. But what do we mean by "the mind"? The mind encompasses the thoughts, but it is more than that. It's the will deep within the core of our being, our hearts. Will drives thought and we are born corrupted to our very core by sin. Influenced by the will is our brain which is corrupted along with the rest of our body. So our corrupted will takes control of our corrupted brain and breeds even more corruption.For those who are according to the flesh set their minds on the things of the flesh... For the mind set on the flesh is death... because the mind set on the flesh is hostile toward God; for it does not subject itself to the law of God, for it is not even able to do so, and those who are in the flesh cannot please God. (Romans 8:5-8 NASB)
But God begins a work of transformation in us when we are saved, changing us into the image of Christ. However, we are not simply passive actors in this process. Nor are we left to fight through this by ourselves. We have a Helper, the Holy Spirit. And what does the Holy Spirit do for us? He reminds us of the words of Christ and the things of God as revealed in Scripture (John 14:25-26).
And there is our answer. This is how we are transformed by the renewing of our minds. The renewing of our minds is a work of the Holy Spirit as he takes the thoughts of God as they are recorded in the Bible and brings them to remembrance. Those thoughts we never would have had before we now find in our minds. Those ideas that before we simply could not understand we now find made clear to us as the Spirit of God works in our minds and transforms us from the inside out so that our thoughts are in harmony with God's thoughts.
So what is our part? To listen! It is our responsibility to hear the words of God by reading the Bible, studying what God has said, going to Church and hearing the faithful exposition of scripture, and thinking about what we have read and heard. Then, as we go through our day we will find that those words are coming back to us. When tough times come promises and commandments of God that we read long ago leap back into our minds. When sin tempts us we remember what God has said and are convicted. When it is time for us to bear witness to Christ, the words of scripture are ready in our tongues.
At those moments we have a choice. We can obey or fight. This is what Paul is talking about when he says "Do not be conformed to this world, but be transformed by the renewing of your mind". We are to push aside the old mind set on the flesh allow the Spirit of God to cause the word of God to so richly dwell within us (Colossians 3:16) that it changes our very thoughts and brings them captive to the obedience of Christ (2 Corinthians 10:5) resulting in our lives being radically transformed from the inside out. The Spirit of God spends His ministry working this transformation within us, but it is not unilateral. We have the opportunity to work with Him and to accelerate the process as we listen and obey.
Let's take another look at Romans 8:5-14 and see how this comes together.
If you do not have the Spirit you are unable to think clearly. If you do not have the Bible and read it you are starving your mind of the food the Spirit uses to transform you. If you do not listen to the promptings of the Spirit then you are setting your mind on the flesh and fighting against the change that God is making within you.For those who are according to the flesh set their minds on the things of the flesh, but those who are according to the Spirit, the things of the Spirit. For the mind set on the flesh is death, but the mind set on the Spirit is life and peace, because the mind set on the flesh is hostile toward God; for it does not subject itself to the law of God, for it is not even able to do so, and those who are in the flesh cannot please God.However, you are not in the flesh but in the Spirit, if indeed the Spirit of God dwells in you. But if anyone does not have the Spirit of Christ, he does not belong to Him. If Christ is in you, though the body is dead because of sin, yet the spirit is alive because of righteousness. But if the Spirit of Him who raised Jesus from the dead dwells in you, He who raised Christ Jesus from the dead will also give life to your mortal bodies through His Spirit who dwells in you.So then, brethren, we are under obligation, not to the flesh, to live according to the flesh— for if you are living according to the flesh, you must die; but if by the Spirit you are putting to death the deeds of the body, you will live. For all who are being led by the Spirit of God, these are sons of God. (NASB)