Summary: As a Christian we must yield to the spirit so that we can put off the desires of the flesh.
Putting Off & Putting On
You can tell a lot about people in our society by the way they dress. From baseball players,skaters, to bus drivers, from postal carriers to policemen, people wear the uniform of their profession. Who we are determines what we wear, not ¡§dressing the part¡¨ can sometimes have embarrassing consequences. Many years ago a very wealthy man in a Southern California town was found wandering around the local country club wearing shabby clothes. He was in custody by security guards and charged with vagrancy¡Xeven though he owned the country club. He had failed to dress consistent with who he was.
That is exactly Paul¡¦s point in 3:9¡V17. Christians must dress themselves spiritually in accordance with their new identity. This section links 3:5¡V9a, which tells believers what to put off, and 3:12¡V17, which tells them what to put on. This is the bridge between the old self and the new self
1. The Position of the New Man verse 9b-10a
since you have taken off your old self with its practices. and have put on the new self,
„Ã The word ¡§since¡¨ acts the transition from the old self to the new self. The relation of the old self and the new self has been much disputed.
View # 1 Many hold that at salvation believers receive a new self but also keep the old self. The argument that the struggle in the Christian life comes from the battle between the two.
„Ã This view however is not Biblical, Paul throughout his epistle said,
2 Cor. 5:17 - Therefore, if anyone is in Christ, he is a new creation; the old has gone, the new has come! Romans 6:6 - For we know that our old self was crucified with him so that the body of sin might be done away with, that we should no longer be slaves to sin--
A. The Old Self
„Ã Paul in Ephesians (Colossians twin epistles)
Ephes. 4:25-32 Therefore each of you must put off falsehood and speak truthfully to his neighbor, for we are all members of one body.  "In your anger do not sin": Do not let the sun go down while you are still angry,  and do not give the devil a foothold.  He who has been stealing must steal no longer, but must work, doing something useful with his own hands, that he may have something to share with those in need.  Do not let any unwholesome talk come out of your mouths, but only what is helpful for building others up according to their needs, that it may benefit those who listen.  And do not grieve the Holy Spirit of God, with whom you were sealed for the day of redemption.  Get rid of all bitterness, rage and anger, brawling and slander, along with every form of malice.  Be kind and compassionate to one another, forgiving each other, just as in Christ God forgave you.
B. The New Self
Ephes. 4:17-24 So I tell you this, and insist on it in the Lord, that you must no longer live as the Gentiles do, in the futility of their thinking.  They are darkened in their understanding and separated from the life of God because of the ignorance that is in them due to the hardening of their hearts.  Having lost all sensitivity, they have given themselves over to sensuality so as to indulge in every kind of impurity, with a continual lust for more.  You, however, did not come to know Christ that way.  Surely you heard of him and were taught in him in accordance with the truth that is in Jesus.  You were taught, with regard to your former way of life, to put off your old self, which is being corrupted by its deceitful desires;  to be made new in the attitude of your minds;  and to put on the new self, created to be like God in true righteousness and holiness.
Question: Why Do Believers Sin, if the Old Self is Gone?
They do so because the new self lives in the old body and must contend with the flesh. Paul shows this in the conflict described in Romans 7:14¡V25. After a person is regenerate, old value systems, priorities, beliefs, loves, and plans are gone. Evil and sin are still present, but the believer sees them in a new perspective, and they no longer control him.
 I do not understand what I do. For what I want to do I do not do, but what I hate I do.  And if I do what I do not want to do, I agree that the law is good.  As it is, it is no longer I myself who do it, but it is sin living in me.  I know that nothing good lives in me, that is, in my sinful nature. For I have the desire to do what is good, but I cannot carry it out.  For what I do is not the good I want to do; no, the evil I do not want to do--this I keep on doing.  Now if I do what I do not want to do, it is no longer I who do it, but it is sin living in me that does it.  So I find this law at work: When I want to do good, evil is right there with me.  For in my inner being I delight in God’s law;  but I see another law at work in the members of my body, waging war against the law of my mind and making me a prisoner of the law of sin at work within my members.  What a wretched man I am! Who will rescue me from this body of death?  Thanks be to God--through Jesus Christ our Lord! So then, I myself in my mind am a slave to God’s law, but in the sinful nature a slave to the law of sin.