sinful nature vs. the Spirit

So my brother and I have been emailing back and forth about what it looks like to be a believer or follower of Christ.  One thing I have wrestled with and brought up to him are the verses in Romans 10 that state, "9If you confess with your mouth that Jesus is Lord and believe in your heart that God raised him from the dead, you will be saved. 10For it is by believing in your heart that you are made right with God, and it is by confessing with your mouth that you are saved."  To me, It doesn't seem like saying a lil prayer stating the Jesus is Lord and thanking him for dying on the cross for you is enough if you continue on living by your sinful nature.  What do you think?!  There have certainly been times in my life when I have lived in such a way -- just banked on the fact that because I asked Jesus to come into my heart at the age of four, then I could go on doing my own thing knowing that I would still end up in heaven some day.  Ya know ... I do not want to discredit our Savior's grace and sacrifice on the cross, but I am not convinced that living in such a way qualifies as being a believer in Christ who will one day be a part of His eternal kingdom.  Check out this excerpt from Romans.  It's long, but worth reading.

Romans 8:5-13
5Those who live according to the sinful nature have their minds set on what that nature desires; but those who live in accordance with the Spirit have their minds set on what the Spirit desires. 6The mind of sinful man is death, but the mind controlled by the Spirit is life and peace; 7the sinful mind is hostile to God. It does not submit to God's law, nor can it do so. 8Those controlled by the sinful nature cannot please God.
9You, however, are controlled not by the sinful nature but by the Spirit, if the Spirit of God lives in you. And if anyone does not have the Spirit of Christ, he does not belong to Christ. 10But if Christ is in you, your body is dead because of sin, yet your spirit is alive because of righteousness. 11And if the Spirit of him who raised Jesus from the dead is living in you, he who raised Christ from the dead will also give life to your mortal bodies through his Spirit, who lives in you.
12Therefore, brothers, we have an obligation—but it is not to the sinful nature, to live according to it. 13For if you live according to the sinful nature, you will die; but if by the Spirit you put to death the misdeeds of the body, you will live.

To me, that kinda clears it up.  I am convinced that if we truly have accepted Christ's gift of grace and salvation and have a relationship with Him, then our lives will be transformed by the power of His Holy Spirit.  No longer will out actions and words and minds be controlled by our sinful nature.  That does not mean that we will not sin at all.  In fact, 1 John 5:18 says, "We know that God’s children do not make a practice of sinning, for God’s Son holds them securely, and the evil one cannot touch them."  I believer that there is a difference between sinning and making a practice of sinning. 

A believer does not know that going out on a Saturday and getting drunk is wrong and yet does it anyway.  That is practicing sin.

A believer does not choose to have sex with his or her bf/gf, even though they know it is wrong and feel condemned.  That is practicing sin.

A believer does not recognize that cheating on an exam is wrong, and yet goes ahead and does it.

I believe that someone who has the Holy Spirit in them is intentional about not sinning, although slip-ups will occur. And that individual desires Christ to work on their heart and mind in a way that protects them from getting caught up in the sinful things around them.   And although it may be a slow process to reaching that point, a believer goes to their Savior in prayer until they are strong enough to give up the sinful things of this world.  As my brother put it, "I think that if your life looks no different as a 'follower of Jesus' then it did before you became a 'follower'... then you are just a pretender. And you can't pretend with God because he knows your heart... it's all about your heart!"

My hope is that we can all start to really reflect on our lives and seek out how to align our actions and the desires of our hearts with what honors Him.  Please pray for me, personally, that my life can continue to be transformed by His Spirit through this process of learning to live a life of eternal value.  

K thanks for reading.  Grace and peace♥