2 Peter 1.3-4:
His divine power has granted to us all things that pertain to life and godliness, through the knowledge of him who called us to his own glory and excellence, (4) by which he has granted to us his precious and very great promises, so that through them you may become partakers of the divine nature, having escaped from the corruption that is in the world because of sinful desire. (ESV)
Obedience as a frame of mind doesn’t really come naturally for us. Apart from the action of God in our lives, we would have no hope of even aspiring to live a life pleasing to him. And even after accepting Christ as Savior, our sinful nature is still present within us. I’ve met people who believe that our sinful nature is taken away upon salvation, and some assert that a person can come to the point of living a sinless life. But there is no direct, express statement in the New Testament that says when a person becomes a Christian, his or her sinful nature is taken away.
The verses above teach that a Christian is made a partaker of the divine nature. This is by the Holy Spirit, who lives in every Christian. And he gives us the power to say “no” to sin and temptation. So what results from this is that there is a very practical tug of war going on within us. We have ongoing choices to make about how we conduct our lives. And it is in this way a Christian’s free will and life of obedience is genuinely put to the test.
Without our sinful nature there would never be true tests in our lives, giving us the opportunity to choose God’s way for us, rather than the wrong way. Without being made partakers of the divine nature there would be no true internal desire to obey. And so it is by this conflict and battleground that our true allegiance and faithfulness to God is demonstrated and lived out. When Romans 6.12 gives us the exhortation and command, “Let not sin therefore reign in your mortal body”, it means that it is very possible for this still to happen. Otherwise, why give the command?